WERNER MARCHAND 85 



tains the openings of the tracheal trunks. On the other hand, this 

 spine has no connection with the anus, which is not terminal, as 

 Walsh assumes, but lies in the fleshy tubercle of the eleventh seg- 

 ment, where Walsh observed "a deeply impressed, longitudinal stria." 



The larva described by Walsh and which undoubtedly was Tahanus 

 atratus, at least that specimen from which he obtained an imago, is 

 found according to him from the beginning of June to the beginning 

 of September, at which latter time he also met with a specimen only 

 half the length of the full grown specimen (possibly belonging to a 

 different species). 



The pupa has also been described by Walsh, and the description is 

 given here without change: 



''The pupa (from the pupal integument) is cylindrical, suddenly rounded at the 

 head, and tapering a little in the last two abdominal joints; the color is a very 

 pale, semitransparent, yellowish brov/n. The mouth is represented by six tu- 

 bercles, hexagonally arranged, above which, upon each side, is a trigonate three- 

 or four-jointed antenna, pointing outwards. The pronotum commences immedi- 

 ately behind the antennae and bears on its anterior dorsal submargin a pair of 

 reniform tubercular spiracles, the mesonotum, to which the wing cases are at- 

 tached, is twice as long as the pronotum, and bears on its anterior dorsal margin 

 a pair of obliquely placed reniform tubercular spiracles, three times as long as 

 the prothoracic ones. Then follows a very short metanotal piece, about one- 

 seventh as long as the pronotum, bearing no spiracle, which is succeeded by 

 eight subequal segments, all but the last bearing on their lateral dorsal surface a 

 subbasal round tubercular spiracle. The first of these eight segments is simple 

 and extends to the tip of the wing cases i^"* the others are all furnished two-thirds 

 of the way to their tips with an annulus of appressed bristles directed back- 

 wards. The anal thorn is very robust, having a diameter of one-half the last 

 abdominal segment, and is squarely truncate as soon as its length is half its width, 

 and terminates in six small robust thorns, arranged in a regular hexagon. Length 

 0.97 inch; greatest diameter 0.21 inch. One specimen." 



The second author to describe the larva of Tahanus atratus was 

 C. V. Riley (1870). His description of the larva is quoted by Salmon 

 and Stiles. ^^ 



^■^ 'T beheve this first spiracle-bearing segment to be metanotal, as also the 

 corresponding piece in the pupa of Midas fulvipes, u. v.," (Walsh). 

 ^^ Salmon and Stiles, Emergency report on surra, pp. 100 and 101. 



