237 



The description of the larva of Trimicra pilipes Meigen is not un- 

 like that of the present species, but in the former the locomotor organs 

 consist of paired pseudopods, and it is probably a true pediciine species, 

 whereas the one above described may prove to be an aberrant limno- 

 biine, resembling Pediciinae only in the structure of the apical seg- 

 ment. 



Genus incertus 3 



This is the larva described and figured by Mr. Hart as Brioptera 

 species (a). Judging from the characters of the larvae of Brioptera 

 summarized on a previous page this species does not belong to that 

 genus. The head is quite different from that of Helohia, the dorsum 

 being much more compact, as is shown in Figure 19, Plate XXXIV. 

 I believe that the species really belongs to Eriopterinae, as the super- 

 ficial characters ally it more closely with that subfamily than with any 

 other. The larva and its apical segment are shown in Figure 8, Plate 

 XXIX, and in Figure 5, Plate XXX, respectively. 



For a full description of the species see Mr. Hart's description*. 



The larva lives among floating weeds in the Illinois River. 



Genus incertus 4 



Larva. — Length, 15 mm. Slender, the segments distinctly longer 

 than broad, the body of almost uniform thickness. 



Head very similar to that of Helohia, the median posterior rod 

 even more slender than in that genus; dorsal plate (fronto-clypeus) 

 longer and more slender and pointed than in Helohia; maxillary palpi 

 tapering, extending very much beyond the apex of labrum, with dis- 

 tinct constrictions on apical third, giving them the appearance of hav- 

 ing 3 joints. Body covered with dense yellow decumbent pile, most 

 conspicuous at posterior margins of thoracic segments because there 

 it is slightly turned upward. Abdomen without distinct locomotor 

 organs ; penultimate segment swollen much as in Hexatominae ; apical 

 segment with 4 short backwardly directed protuberances, the upper 

 . pair distinctly shorter than the lower ; anal blood-gills inconspicuous. 



The foregoing description was made from a specimen in the 

 Laboratory collection bearing the accession number 26785, the ac- 

 companying data being as follows : Blacktail Deer Creek, Yellow- 

 stone National Park, August 28, 1890; taken under stones in the 

 water (S. A. Forbes). 



*Bull. 111. state Lab. Nat. His. Vol. 4, Art. Yj, pp. 198-199. 



