82 THE EARLY STAGES OF TABANID^ 



to burrow and are soon beneath the surface, where they cannot be 

 seen. At first these larvse are very hard to see on account of their 

 small size; consequently not much has been learned of their habits 

 under natural conditions; but when they are nearly grown they are 

 to be found in a variety of places. We now come to a discussion of 

 the adult larval stage. 



Walsh (1863) gives a description of an aquatic Tahanus larva which 

 he was unable to identify as the imago obtained from this larva was 

 in too bad a condition to be identified, having remained many weeks 

 without care, in the breeding jar. From his descriptions, however, 

 and also from his remarks on the imago, it is evident that the larva 

 belongs to Tabanus atratus. There is in Massachusetts no other 

 Tahanus known of this size and with wholly brownish black wings, 

 and the description of the larva agrees with that given by later 

 authors for undoubted Tahanus atratus larvae. However, some of 

 Walsh's smaller specimens may belong to Tahanus stygius or other 

 species. 



Walsh found his aquatic larva, on many different occasions, 

 "amongst floating rejectamenta." On one occasion he found six 

 or seven specimens in the interior of a floating log, so soft and rotten 

 that it could be cut like cheese. Once he discovered a single speci- 

 men under a flat submerged stone, in a little running brook. Finally, 

 once he met with one alive, under a log, on a piece of dry land which 

 had been submerged two or three weeks before, whence it appears that 

 it can exist a long time out of the water. Walsh had, on several pre- 

 vious occasions, failed to breed this larva to maturity, and the only 

 imago he had was obtained in 1861 from larvae which, suspecting 

 them to be carnivorous from the very varied stations in which they 

 had occurred, he had supplied with a number of fresh water mollusks, 

 but the habits of which, in consequence of having been away from 

 home, he was unable to watch. On September 2, 1863, he found a 

 nearly full grown larva among floating rejectamenta, and between 

 that date and September 23 this larva devoured "the mollusks of 

 eleven univalves" (genus, Planorhis) from one-half to three-fourths of 

 an inch in diameter; and on three separate occasions observed it work 

 its v/ay into the mouth of the shell. In this operation the pseudopods 

 were energetically employed and Walsh found, on cracking the shells 



