igio] A Structural Study of Some Caterpillars 121 



a level with them;. basal joint of antenna nearly as long as second 

 joint, which is short, submenta heavily chitinized and well sep- 

 arated. Body with tufts representing i+ii, Hi, iv + v, vi, vii, 

 and viii, with only two, therefore, above the spiracles, while 

 there are three in the Arctiid types. Pro legs with a single unin- 

 terrupted row of hooks, all of the same length ; no prolegs on third 

 segment of abdomen. 



ExHrn])le Nola cucullatella. 

 PSYCHIDAE. 



Prolegs with hooks all the same length, in a circle broken postero- 

 mesally; anal legs similar to the others. Adfrontals massive, their 

 setae well separated, not reaching far above the top of front; ii of epi- 

 crania close to them; frontal setae far apart, punctures close together 

 and somewhat lower; antennae normal with short second joint; pro- 

 thoracic spiracle piercing the cervical shield ; .labrum with vi not on 

 the margin. Mera of true legs much enlarged and nearly or quite 

 meeting in the middle line; all segments of the thorax with dorsal 

 plates. Body with setae i and ii variable, iv and v close together, 

 vii variable, ii of ninth abdominal segment distant from each other. 



Solenobiinae: True legs very long, and slender; front twice as 

 high as wide ; abdomen with ii lower than i, normal ; prolegs with about 



15 hooks. 



Example Solenobia pineti. 



Psychinae: True legs short and very stout; front shorter; abdo- 

 men with ii higher than i: prolegs with over 20 hooks. 



Front nearly as wide as high; ii of abdomen almost directly over i; 

 Example Thyridopteryx ephemeraeformis. Figs. 128 and 134. 



Front half higher than wide; ii of abdomen on the next annulet 

 behind i. 



Example Psyche zelleri. Fig. 127. 



COSSIDAE. 



Prolegs with hooks in an uninterrupted circle, alternately of three 

 lengths, but with no great difference between the three lengths; the 

 anal legs with hooks in a curved band. No secondary or tufted hair. 

 Epicrania separated by a membranous area at the vertex, a slender 

 prolongation of the adfrontals reaching the vertex; head not retractile. 

 Front higher than wide; the setae far apart and the ptmctures close 

 together, level with the setae. Adfrontals large, reaching vertex, 

 the setae rather close together, opposite the upper half of the front. 

 Labrum with a shallow notch, i, ii, Hi, and iv nearly on a level, 

 none of the setae quite on the margin; mandibles extend forward with 

 the cutting edge turned upward lor gnawing wood. Af axillary palpi 

 with second joint very wide and massive, bearing the large cones, which 

 turn inwatd as in the Hepialidae; the galea arises from its apex as in 

 other Frenatae, and is quite small. Labium normal with sclerites b 

 massive, and c slender; palpi rather short; submenta not in contact. 

 Prothoracic spiracle distant from cervical shield; body with setae as in 



