20(j 



cited, the description of the imago being given on page 80. The 

 species stands in the Loew collection at Cambridge, Mass., under the 

 name bicornis Loew, but never was described by Loew. 



Mr. Hart, in his "Entomology of the Illinois River and Ad- 

 jacent Waters" unfortunately entered in his key the larva of ainctans 

 as that of bicornis. 



The larva of bicornis is almost inseparable by superficial charac- 

 ters from that of Pachyrrhina fcrriiginea, but possibly with better 

 and more material than I have, such separation may be feasible. In 

 examples which I have dissected I find that the labial plate and 

 hypopharynx furnish characters that appear to be of specific value. 

 These differences are shown in Figures 12 and 13, and 14 and 15, 

 Plate XXXII. 



The pupae of the two species are also very similar in structure, 

 and I find in the shape of the apical segment of the females the only 

 appreciable distinction. This difference is illustrated by Figures 5 and 

 7, Plate XXVIII. The apical segment of the male pupa may pro- 

 vide characters for the separation of this sex also; I have no male 

 pupa of bicornis for examinatfon. 



The species is very widely distributed in this state, and is some- 

 times destructive to pastures, the larvae feeding on the roots of the 

 grasses. 



Pachyrrhina ferruginea Fabricius 



Tipula ferruginea rabricius, Sept. Antl., Species 28. (1805) 



The larva (PI. XXVIII, Fig. 4) of this species bears a striking 

 resemblance to 7\ bicornis and is found in the same situations. I 

 have no well-preserved specimens of authenticated bicornis for com- 

 parison of the external characters with those of ferruginea. The 

 frontal plate is as in Figure 10, Plate XXXI, and dissection of the 

 head shows the distinctions mentioned under bicornis (see PI. XXXII, 

 Figs. 14, 15). Apical abdominal segment as in Figure 3, Plate XXX. 



The pupa is also very similar to that of bicornis, the only charac- 

 ters that appear to be useful in their separation being found in the 

 apical abdominal segment-as stated in key. (See PI. XXVIII. Figs. 5, 

 10, 12.) 



The species is common and widely distributed in Illinois. 



Principal Papers on North American Tipulidae 



Hart, C. A. 



'95. On the entomologv of the Illinois River and adjacent waters. 

 Bull. 111. State Lab.' Nat. Hist., Vol. 4, Art. VI. 



