WERNER MARCHAND 177 



Tabanus sp. No. 5. — (Hart's sp. b.) Hart reports that, in col- 

 lecting the larvae of Limnophila and Bittacomorpha in the swampy 

 slough of Station I, many small tabanid larvae were found in the mud 

 and debris, and among them occurred, on April 15, two examples of a 

 distinct very white form with faint markings like those of stygius, 

 but laterally striate more like atratus, and with a conspicuous isolated 

 smooth spot in the lateral striated area of the pro thorax. He de- 

 scribes the larva as follows: 



"Larva. — [Plate 3, Fig. 42.1 Length 22-23 mm., width 2.5 mm. Very pale 

 whitish, markings like those of stygius, but pale yellowish fuscous and incon- 

 spicuous. Head pale brownish." 



"Lateral prothoracic areas not more than half as long as the dorsal, striation 

 scarcely visible, microscopically fine and opaque, much finer than that of the 

 middle and lower lateral areas of the mesothorax, which are somewhat shining; a 

 rather large smooth spot included in the striated lateral area of the prothorax, 

 not far from the shining ventral area but entirely isolated from it; remaining 

 upper lateral thoracic areas distinctly more coarsely striated than the areas be- 

 low them, and quite shining; abdominal lateral areas more finely striate, feebly 

 shining, microscopically striate on the posterior portion of each area. Dorsal 

 and ventral areas shining, with sparse marginal striae interrupted on the disks, 

 those of thorax especially smooth." 



"Dull annuli broad, including the false feet, a distinct transverse dorsal and 

 ventral pale spot in front of the false feet. Lateral prothoracic area occupied by 

 a very pale fuscous opaque quadrate spot in front of the striated area. Meso- and 

 metathoracic lateral stripes usually visible, but slender, not dilated, lateral edges 

 of dorsal areas diverging; lateral stripes of abdomen almost wanting, except on last 

 two or three segments. Last segment with bases of respiratory tube and anal 

 prominence ringed with opaque fuscous, that around anal prominence sending 

 up an indistinct stripe, with posterior extensions. Pubescence of false feet 

 whitish or pale fuscous. Respiratory tube slender, no spine protruding." 



Tabanus sp. No. 6. — Malloch (1917) describes briefly, and without 

 illustrations, an unknown tabanid larva, which differed from other 

 larvae he had before him, in being entirely white and without lines or 

 patches of pubescence, as well as in being more robust, and less 

 tapered at the extremities. In general appearance it very closely 

 resembled an asilid larvae, the resemblance being accentuated by the 

 small size of the locomotor organs; and it stood as "Asilidse" in the 

 Illinois State Laboratory collection. The specimen was obtained in 

 Pulaski, Illinois, June 1, 1910, in a pit-cage used in rearing white 



