The fifth-stage nymph (Plate XLIV, 54) Length 3.35 mm.; greatest width, across wing pads, 1.61 mm. Length of antenna 1.38 mm. The general color similar to that of the previous stage, but the head and thorax now distinctly patterned. Epicranial suture as in previous stages. The part of the head back of the epicranial suture uniformly dark red. Rostrum yellowish with brown lines on each side, which meet behind the rostrum and then diverge outward until they join the brownish border inside the epicranial suture, thus producing on the head four yellowish patches separated by the brown lines in the shape of the letter X. Prothorax dark brown, punctate with circular yellow spots. From these spots, short white hairs arising. Transverse dark bands on the prothorax, as indicated in Plate XLIV, 54. Rest of thorax, including wing pads, dark brown. The surfaces of meso- and metathorax and the wing pads punctate with yellowish spots, less numerous than those on the prothorax, however. The bases of the wing pads indicated by light-colored, diagonal lines. The margin of the entire thorax and wng pads of a blackish brown color. Wing pads reaching to about the middle of the third abdominal segment. Abdomen colored much as in the preceding stage. The adult (Plate XLIV, 52) Female, length 5.4 mm.; greatest width, across the prothorax, 1.5 to 1.6 mm. Length of antenna 1.75 to 1.85 mm. General color dark brownish red. Posterior margin of head and area around eyes and ocelli black. Sides of rostrum black. Basal segment of antennae black, second and third segments of antennae yellowish brown with fuscous at the bases and apices, and the fourth segment dark red. Head and thorax thickly covered with dark punctures. Pronotum with two wavy transverse dark bands near the anterior margin. Corium pale yellowish brown with two black spots on the disk and four black spots on the inner lower margin. Legs reddish brown. Apical segments of tarsi black. Body covered with a very fine white pile. Male slightly smaller than female. Siphocoryne nymphaeae Linn." Siphocoryne nymphaeae Linn., the reddish brown plum aphis, is found in numbers on cat-tail during the spring and summer. This species also uses other water plants as its summer hosts, such as Nymphaea, Potamogeton, and others. The aphids are found on the surfaces of the leaves from the sheath out to the tip of the leaf. The writer observed this species on Typha latifolia at Ithaca in 1915, 1916, and 1918. Aphis avenae Fab.8 The author found Aphis avenae Fab., the oat aphis, in large numbers, feeding on cat-tail, during the spring and summer of 1917, at Lawrence, ? Determined by Dr. Edith M. Patch. 8 Determined by J. J. Davis. Kansas. Frequently the young aphids were found behind the sheaths. of the leaves, in the gelatinous material below the surface of the water in which the plants were growing. Rhopalosiphum dianthi Schrank Rhopalosiphum dianthi Schrank was reported on cat-tail by Sanborn (1906). Rhopalosiphum persicae Sulz. Rhopalosiphum persicae Sul. was reported on Typha latifolia and on T. angustifolia by Wilson and Vickery (1918). Aphis gossypii Glov. Aphis gossypii Glov. is found in small numbers on Typha latifolia during the spring and fall, according to Davidson (1917:65). Macrosiphum granarium Kirby Macrosiphum granarium Kirby, the grain aphis, is found in great numbers on Typha during the summer and fall, according to Davidson (1917:65). Hyalopterus arundinis Fab. Hyalopterus arundinis Fab., according to Davidson (1917:65), is found from April to June. The infestation on cat-tail is never large. There are four to ten generations. Aphids settle mainly on both sides of the blades, locating in colonies, usually not far from the tips. HYMENOPTERA9 Five species of parasitic Hymenoptera were reared on insects which were found on cat-tails. Aleiodes intermedius Cress Aleiodes intermedius Cress was reared on larvae of Arsilonche albovenosa. On August 12, 1916, six specimens emerged from one larva. 'Determined by C. F. W. Muesebeck. Apantales cinctiformis Vier. Apantales cinctiformis Vier. was reared on larvae of Nonagria oblonga. A number of specimens emerged on August 8, 1916. Elachertinae sp. Five specimens of Elachertinae sp. were reared from a larva of Lymnaecia phragmitella. These emerged on June 15, 1916. Pimpla indagatrix Walsh On June 8, 1916, several specimens of Pimpla indagatrix Walsh emerged from the heads of cat-tails which had been kept in a covered jar in the laboratory. Pimpla inquisitoriella D. T. Several specimens of Pimpla inquisitoriella D. T. were reared from pupae of Arsilonche albovenosa. DIPTERA 10 The following flies were reared from cat-tail. Platychirus quadratus Say Platychirus quadratus Say was reared from the heads of cat-tail. The larvae were noticed in early spring in the overwintering cat-tail heads. Many adults emerged between May 21 and June 10. Macrosargus clavis Will. The larvae of Macrosargus clavis Will. live in the burrows made by the larvae of Arzama obliqua Walk. or of Nonagria oblonga Grote. They winter over in the larval stage, and the adults emerge in May and in early June. Chaetopsis aeneae Wied. The larvae of Chaetopsis aeneae Wied. also are found in the burrows of Arzama obliqua Walk. and of Nonagria oblonga Grote. Adults emerged on August 8. 10 The first three species were determined by Dr. O. A. Johannsen, the last one by Dr. J. D. Tothill. Sturmia nigrita Town. Sturmia nigrita Town. is a parasite which was found living in the larva of Arzama obliqua Walk. In each of the two instances observed, there was only one parasitic larva present in each of the larvae of Arzama obliqua. Both dipterous larvae emerged from their host on March 25, 1918, through an opening which was made on the ventral side of the first thoracic segment. They pupated on the following day, and one adult emerged on April 9 and the other on April 10. RÉSUMÉ From an ecological point of view, the insect inhabitants of Typha may best be considered with respect to the part of the plant they affect. Accordingly they are thus classified in the following pages. INSECT INHABITANTS OF THE HEAD OF TYPHA The insects inhabiting the head of Typha include, among the Lepidoptera, Lymnaecia phragmitella Staint., Dicymolomia julianalis Walk., Archips obsoletana Walk.; and among the Hemiptera, Ischnorrhynchus resedae Panz. The work of L. phragmitella and D. julianalis is very similar. Each has one generation a year. Their early larval habits are almost identical. They feed first on the tender styles of the pistillate flowers of the cat-tail plant, leaving the stigmas to form a covering over themselves. Later, they advance deeper into the head and feed on the seeds and other parts of the fruiting spike. Both overwinter in the half-grown larval stage. In the spring before pupation, however, their habits become somewhat different. Many of the larvae of D. julianalis bore into the rachis of the head, where they transform. The majority of the larvae of L. phragmitella, on the contrary, remain in the pappus of the cat-tail, where they pupate in closely woven cocoons. A few of the L. phragmitella larvae migrate down to the stalk of the plant, where they bore into the stems and transform. The adults of both species emerge at about the same time. L. phragmitella is a species of world-wide distribution, while D. julianalis is generally restricted to the Southern States, though it is found as far north as New York. Of L. phragmitella the writer has found as many as 76 pupae in a single head, while of D. julianalis he has never observed more than six or eight individuals in one head. Both of these insects are well adapted to live in the heads of cat-tail. Both spin an abundance of silk whereby they tie the pappus together and keep the head from being torn and the seeds from being scattered. This process of tying the pappus together assures the larvae of retaining their food supply and also furnishes them a protected and sheltered place for passing the winter. D. julianalis, however, being a less hardy southern form, was unable to stand the severe temperature during the winter of 1917-18, and all the larvae found in the Typha heads that spring were dead. Archips obsoletana should probably be classified as an incidental feeder on cat-tail. It is a typical leaf-roller, occurring chiefly on strawberry plants. However, once the larvae locate on the head of the cat-tail, they spend the entire larval period there and transform to the pupal stage on the plant. Since there are three generations a year, it is very probable that never more than one generation is passed on cat-tail; for these insects feed only on the tender styles of the pistillate flowers, and as these soon dry up, the later generations would not be able to find the tender food they relish. When living on the strawberry plant, these larvae roll themselves up in a leaf for protection. On the head of cat-tails they protect themselves by tying the stigmas together underneath with a lining of silk, thus forming a cover under which they live while feeding on the styles of the flowers. When placed in a cage with cat-tail leaves, the larvae prepare a covering for themselves by tying two leaves together and crawling between them. At the time of pupation they tie a leaf to the head of the plant and thus obtain the protection necessary during their transformation. In the spring, the females of Ischnorrhynchus resedae deposit their eggs in the old, downy heads of the cat-tail. The eggs closely resemble the seeds of cat-tail and thus are well protected from enemies. Immediately after hatching, the nymphs begin to feed on the seeds of the plant. They thrust their beaks into the dry seeds and apparently obtain their nourishment by injecting saliva into the seeds, which dissolves the solid material there so that they can suck it up into the body. The entire nymphal stage is spent in feeding on the dry seeds, a very remarkable and interesting adaptation. Due to the work of L. phragmitella and D. julianalis, the seeds of many of the old heads are kept from being scattered by the winter storms, and Ischnorrhynchus resedae simply takes advantage of these |