WERNER MARCHAND 53 



connection with those of Bittacomorpha, Limnophila, and Sialis, in 

 the weedy, swampy little stream at Station I of his entomological 

 survey of the Illinois river valley. They were quite common here, 

 occurring in the mud and the mats of dead stems, rarely floating at 

 the surface. The first were seen March 28, but they continued to 

 occur up to April 15, increasing slightly in size. In the breeding cage 

 they burrowed in the mud and through the vegetation. 



In the latter part of May the water was allowed to dry up and on 

 the 28th all that remained was poured off. From June 1 to 3 three 

 pupae were formed in the damp mass of dead vegetable matter resting 

 on the mud in the cage. Two imagos emerged June 9, both males, 

 the third failing to transform. 



The coloration of the larva readily distinguishes it from other 

 known tabanid larvae. Hart's description of larva and pupa is quoted 

 below. 



"Larva. — [Plate 3, Fig. 39. P" Length 10-15 mm., diameter 1.6 mm. Head 

 light colored, mouth parts pale, tips of maxillary palpi in line with end of labrum; 

 body whitish, a mottled appearance within, at the middle of the body." 



"Dorsal and ventral areas striate, striae entire, distinct, and not very fine, 

 the lateral striation a little finer, that of the prothorax very fine, with a small 

 smooth spot adjoining the smoother surface of its ventral area; the latter shorter 

 than the dorsal, not including the anterior pair of setae; median sulcus scarcely 

 dull-pubescent. Meso- and metathorax with lateral impressed lines, and 

 dull-pubescent pale annuli, but the lateral lines almost without pubescence. 

 Fleshy false feet of abdominals rather prominent, dorsal pair united into one, 

 there being no narrowing near the median line; annuli very pale except on the 

 last two or three segments; last segment white basally, the remainder covered 

 with dull blackish microscopic pubescence reaching forwards to the anal promi- 

 nence, a triangular extension each side of the middle above, often a small spot 

 accompanying each; respiratory tube whitish, spine sometimes projecting." 



"Tracheal trunks sinuate posteriorly, crossing and recrossing in front of the 

 middle." 



"Pupa. — [Plate 13, Figs. 154 and 157.] Length 9-10 mm., diameter 2 mm. 

 Light brownish, ferruginous, obsoletely transversely wrinkled, head and thorax 

 shining, abdomen duller." 



^^ In the quotations, as well as in the rest of the paper, the figure numbers 

 refer to the illustrations in the present monograph. 



