August, 1944 



Ross: Caddis Flies of Illinois 



197 



them have failed. The larvae are about 15 

 mm. long, the head and pronotum are yel- 

 lowish brown with brown spots, and the 

 gills at the base of the abdomen are short 

 and very bushy, each forming a compact fan 

 with 10 to 12 filaments, fig. 616. These 

 agree perfectly with the description of the 

 European species of this genus, the peculiar 

 gills being diagnostic. The case is usually 

 slightly curved and made of wood frag- 

 ments. 



We have taken these larvae in temporary 

 ponds and in small streams, most of which 

 became dry in summer. In each collection 

 we made, the larvae were full grown late 

 in April or early in May. They appear to 

 aestivate under roots and other objects close 

 to or under the bank of the stream or pond. 

 We never were able to locate the larvae 

 after the stream or pond dried up, and the 

 cultures which we had in cages in various 

 streams were all killed by a fungus growth. 

 Our adult records are all late in the season, 

 ranging from September into October, al- 

 though in other states adult records are 

 earlier. It is very likely that this genus has 

 essentially the same habits as Neophylax 

 (see p. 202). 



As it is impossible to be sure of the asso- 

 ciation of any of the larvae with definite 

 species, the records of the larvae for the 

 entire genus are grouped together as fol- 

 lows. 



Illinois Records of C abortus Larvae: 

 Des Plaines, Fox River: May 26, 1936, 

 H. H. Ross, 1 larva. Fox Ridge State 

 Park: April 12, 1941, B. D. Burks, 1 larva. 

 Hurd, small stream: April 15, 1936, Ross 

 & Mohr, many larvae. Oakwood: April 

 10, 1936, Ross & Mohr, 1 larva; May 6, 

 1936, Ross & Mohr, 2 larvae; May 7, 1936, 

 Ross & Mohr, 1 larva. Rantoul, tempo- 

 rary pond: April 10, 1936, Ross & Mohr, 

 1 larva. Red Bud: March 23, 1939, Ross 

 & Burks, 2 larvae. Seymour: March 20, 

 1929, H. H. Ross, 1 larva. Watson: April 

 15, 1936, Ross & Mohr, 2 larvae; April 16, 

 1936, Ross & Mohr, 1 larva. 



KEY TO SPECIES 

 Adults 



1. Maxillary palpi 3-segmented (males) 2 

 Maxillary palpi 5-segmented (females) 3 



2. Apex of aedeagus cleft and lyre shaped 



at apex, claspers rounded at apex, 

 fig. 684 lyratus, p. 198 



Apex of aedeagus divided into a pair 

 of bulging, sharp plates with a mem- 

 branous dorsal pocket, claspers 

 bluntly pointed at apex, fig. 685. . . 

 punctatissimus, p. 197 



3. Ninth and tenth tergites separated by 



a distinct, suture-like groove; ninth 

 sternite without an internal plate 

 ventrad of bursa copulatrix, fig. 686 



kaskaskia, p. 198 



Ninth and tenth tergites fused and 

 scarcely separable, fig. 687; ninth 

 sternite with a round or rectangular 

 internal plate ventrad of bursa, figs. 

 687, 688 4 



4. Ninth sternite with an internal rec- 



tangular plate ventrad of bursa 



copulatrix, fig. 688 



punctatissimus, p. 197 



Ninth sternite with internal plate 

 much smaller and semicircular, fig. 

 687 lyratus, p. 198 



Caborius punctatissimus (Walker) 



Halesus punctatissimus Walker (1852, p. 

 17); cf. 



Adults. — Length 16-18 mm. Color al- 

 most uniformly yellowish brown, the front 



684 LYRATUS 



685 

 punctatissimus 



Figs. 684-685. — Caborius, male genitalia. 

 A, aedeagus, ventral aspect; B, aedeagus, 

 lateral aspect; C, clasper. 



