WERNER MARCHAND 165 



The young larva is briefly described by Hines as follows: 



"Larva, when first hatched, 4 mm. long; entirely light colored; form as in 

 older specimens. As growth continues size is the only noticeable change." 



The mature Urva has been figured and described in detail by Hart 

 (Plate 3, Fig. 40). This species was the most abundant tabanid 

 larva found in the vicinity of Havana, Illinois, in the spring of 1895. 

 It first appeared in Hart's collections September 14, 1894, when a 

 number were noted swimming among vegetation near the margin at 

 Station B, on the wet springy shore of Quiver Lake, with sandy 

 and muddy ground, grass, and coating of alg£e. In the spring they 

 were, however, found at nearly all of the stations, but more particu- 

 larly in connection with tipulid, muscid, and Er is talis larvae in matted 

 accumulations of dead stems and leaves over mud. They were es- 

 pecially abundant on March 30 in Flag Lake, where large plump 

 larvae appeared at every turn. It was a surprise to find a few of them 

 upon the bottom in the open shallow water, far from shore, in the 

 middle of Quiver Lake at Station A, for which locality Hart gives the 

 characteristics: "Shallow, mud and sand, grass and floating vegeta- 

 tion, variable." Young larvae have been common in connection with 

 larvae of Bittacomorpha and Limnophila, at Station I (see Tabanus 

 atratiis) since March 17. At others of Hart's stations they have been 

 common in moist drifts of fine rubbish washed up by waves. Pupae 

 were formed in the breeding cages May 10 and 23. One emerged 

 May 27, and another tried to emerge June 2, but died and was re- 

 moved from its case. 



The larvce of Tahaniis stygius resemble, accordhig to Hart, those 

 of the lineola group in their striation and coloration, but differ in 

 their short lateral prothoracic areas and larger size. They are like 

 atratus in size, but may be readily separated from it by their coarser 

 lateral striation, straw-yeliow tint, slender lateral pigmented stripes, 

 and usually projecting terminal stigmatal spine. 



Hart's description of the mature larva follows: 



"Larva. — [Plate 3, Fig. 40.] Length 45-55 mm., diameter 6-7 mm. Bright 

 straw-yellow, varying in some young larvae to nearly clear white; marked with 

 light fuscous brown microscopic pubescence, usually paler at each stage than 

 atratus." 



