J. T. Lloyd.
Wood-Boring Trichoptera.
Psyche 22:17-20, 1915.

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19151 Lloyd-Wood-Boring Trichoptera 17
comparison of the insect with Herrich-Schaeffer's figure will show. Ranatra quadridentata Stal No. 152.
The specimen under this
name and number is a typical R. americana Mont. Belostoma americanum Leidy No. 155, Harris No. 109 is Letho- cerus obscurus Duf.
Under the label Notonecta insulata Kirby, No. 156, are placed Harris' Nos. 173 and 176 which Uhler has referred to N. undulata Say in his work cited. He remarks that "It varies also in size, ranging from 9 to 12i millims in length." The discrepancy in size arises from the fact that 176 is N. variabilis Fieb. The other specimens are correctly labelled as they stand. To recapitulate; The following species did not appear in Uhler's paper under their proper names, but as the species with which they are synonymous.
Lyqaus kalmii Stal=L. turckus Uhl., not Fabr. for all except those from Michigan, for the specimens under No. 54. Embletkis vicarius Horv. = Gonianotus marginepunctatus Uhler, not Wolff. for specimen No. 65.
Pelocoris carolinensis Bueno = Nuucoris poeyi Uhler, not Gu6rin, for specimen No. 148.
Ranatra protensa Mont. = R. fusca Uhl., not Palisot de Beauvois, for specimen No. 151.
Ranatra americana MO&. = R. quadridentata Uhl., not Stal for specimen No. 152. (N. B.-This applies to all the specimens from the Northern and Eastern United States, as well as Canada, so determined by myself and others, prior to 1910.) Lethocerus obscurua Dufour = Belostoma americanum Uhl., not Leidy, for specimen No. 109.
Notonecta variabilis Fieb. = 1V. undulata Uhl., not Say, for speci- men 171.
WOOD-BORING TR1CHOPTERA.I
BY J. T. LLOYD,
Ithaca, N. Y.
In the cold, alder-bordered streams of the uplands swamp near Ithaca, N. Y., are found Caddis-worms whose case-making habits 1Contribution from the Limnological Laboratory of the Department of Entomology in Cornell University.




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18 Psyche [February
differ greatly from those of described American Trichopterous larvae. Instead of the usual dwellings of stones or twigs, or tubes of silk, these utilize fallen twigs of wood from the stream-bottom. The twigs are hollowed from end to end, and lined with silk, form- ing portable cases which are a natural part of their surroundings. These belong to an undescribed species, whose larvae abound among the litter of branches and twigs, from the surrounding forest. In spite of their abundance they are most inconspicuous among the debris. They crawl with a jerky motion, as if swayed by the passing current, or rest, as if lodged, on a submerged branch, and when disturbed, let go, drifting down stream with the current. The twigs used as cases vary greatly in length and diameter, apparently being selected at random from the litter on the bottom of the forest stream. Sometimes pieces of heavy bark or frag- ments of broken wood are used. A cylindrical hole always pene- trates the wood from end to end. In some twigs the chamber forks near the anterior end, one outlet curving downward and opening to the exterior at one side, while the other perforates the end of the stick. The side outlet, when present, forms the anterior entrance to the case, the other in the end being plugged with silt or with small pebbles. Sometimes the chamber curves downward without forking, as in Fig. 13. The chamber is always lined with silk. (Fig. 13 represents a case with the silk tube cut away, except around the larva.) Although there is considerable variation in the size of the twigs used their average size increases with the growth of the larvae. To ascertain how the change in cases is made several experiments were made with captive larvae. Some were removed from their cases and put in cages with twigs of appropriate size. These larvae did not attempt touse the wood for making new cases, but merely spun silken tubes to which particles of silt adhered; others, which had one side removed from their cases, repaired the damage with silk and silt. One larva repaired the damaged side with silt and fragments of bark and then proceeded to cut away the two ends of its case. It worked from the damaged side of the case, cutting narrow incisions across the twig until the op- posite side was reached. The operation of cutting the two inci- sions across the twig ten mm. in diameter consumed about 24 hours. Two specimens, which were retained in aquaria in the laboratory, attached the anterior ends of their cases securely, by



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19161 Lloyd- Wood-Boring Trichoptera 19
means of silk, to the ends of solid twigs, and then drilled into the wood, emitting, during the task, an abundance of very finely powdered wood. One of these new dwellings proved too long for its occupant. It was accordingly girdled with a circular incision which was deepened until one end of the twig was completely cut away. Several sticks similarly ringed were found in the creek where the larvae occur. No doubt this is the usual method of changing cases, as larval growth proceeds. The food of the larvae, as demonstrated by examinations of the contents of many stomachs at different seasons, consists of fine powder rasped from submerged wood.
The larvae are active during the summer, fall, and winter. In February, with the thermometer below 20' Fahr., they were ap- parently as active as during the heat of summer. By the end of April they had left the middle of the stream and had firmly at- tached the anterior ends of their cases to some solid support near the streams margin. At this time flat stones were fastened over both ends of their cases, a frequent practice of the larvae at all seasons, during periods of rest.
The specimens in captivity emerged from June 4 to July 11. The wood-boring habits of this species may, when we are famil- iar with more larvse, prove a not uncommon method of case- making. I have found identical cases in streams on the Western slope of the central range of the Colombian Andes, and also in the Valley of the Magdalena River, east of this range. Similar habits are described and figured by G. V. Hudson in "New Zealand Neuroptera" 1904 for Tripleetides obsoleta (Pseudonema obsoleta) of the family Leptoceridae. Hudson, however, states that T. obso- Zeta under natural conditions sometimes constructs cases of frag- ments of leaves.
Following is the description of the wood borer from New York State.
(?) Ganonema nigrum sp. nov.
Length of body 11 mm.; front wing 15 mm.; expanse 32 mm. Dominant color of wings and body dull smoky black. Head black or dark brown with jet black hairs. Antennae dark brown with black hairs. Maxillary and labial palpi lighter brown with black hairs.
Membraneous intersegmental portions light, broken between the head and the prothorax on the venter by a projection of the prothorax and on each side by a similar projection. On each side of the neck there is a white, somewhat



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20 Psyche [February
oval, prominence which bears long black hairs. The chitinous portions of the pro- thorax are black or dark brown with several lighter areas which bear tufts of long black hairs. Ventral side of the prothorax mostly white and unchitinized, except for a narrow median strip which projects backward between the cox= of the meso- thorax. A narrow chitinous plate projects obliquely upward and forward from each front coxa and bears a tuft of long black hairs. The meso- and metathorax are black with narrow borders of lighter color along the sutures. The abdomen has three narrow black lateral lines, the middle one narrowest and extending only as far for- '
ward as the second segment; above and below these lines the color is dark brown, below them it is lighter. One or two gill-like processes, some of which bear black hairs, project from the sides of each of the first five abdominal sutures. The femur, trochanter and tarsus of each leg is rather densely clothed with short black hair. Each fore coxa has two parallel rows of black hairs between which the femur fits when the leg is folded. Each of the two succeeding cox= is provided with a single row of long hairs. For details of the genitalia consult Figs. 2, 3, 4, 5, and 6. Larva: Length 18-20 mm., width 3 mm.
Color of chitinous portions of head
and thorax black when viewed with reflected light, when viewed with transmitted light mounted specimens show faintly lighter markings. The legs are black, ringed with white. Fleshy portions of prothorax and abdomen are pale brownish white. The anal hooks are brown.
The Head is narrowest at its anterior end and broadens very gradually to near its base where it narrows. Behind the place of its greatest diameter it is inclosed within the first thoracic segment.
The distribution of setae on the dorsal surface is shown in Fig. 7. The frons, Fig. 15, has a semicircular line of setse curving away from the cephalic margin and three other, more, widely separated set= near each side. Like the heavily chitinized portions of the head and thorax, the frons is thickly marked by minute transverse lines from each of which arise several very minute hairs, giving except under high power, a somewhat scale-like appearance. The mandibles, Fig. 2 are deeply grooved along their inner margin to the very tip of the apical tooth. Besides the apical tooth, two lateral teeth are present on each edge of the groove. From the groove arise three well-defined brushes of hair. The inner brush is directed inward and backward; the middle and cephalic brushes are directed inward and toward the front; the cephalic brush is the most dense and is composed of extremely fine hairs. The labrum, Fig. 9, is crossed by a row of 18-20 strong sets whose bases almost touch, except on the median line, where there is a greater space. On each latero-anterior angle there is a patch of long fine hairs and in the middle of the cephalic margin a dense line of short hairs. The Thorax: Prothorax heavily chitinized above and on the sides. The area
between and in back of the coxal cavities is membraneous, except two narrow spots immediately in front of the mesothorax. Mesothorax with a chitinous area which extends back over the metathorax as far as the caudal margin of the hind coxee. Within this area there is a well-defined square bearing eight setse, Fig. 7. The sides are not chitinous, except for a small black triangle behind each coxa, which bears a circle of about twelve setse; the venter is free from heavy chitin, except for two narrow yellow spots on the caudal margin. The metathorax is without heavy chitin above. On the sides the distribution of chitinous plates is the same as on



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