WERNER MARCHAND 127 



hooks, the dorsolateral comb is absent, a characteristic which Neave 

 has not seen in the pupa of any other species of Tahanus, except in 

 Tahanus medionotatus . The other combs are, however, striking and 

 characteristic, as may be seen from the figure. 



Tahanus nigerrimus Zetterstedt. — Of this European species we have 

 some indication that it is lignicole in its larval stage. Scholtz (1850) 

 expresses the opinion that perhaps some Tahani live in their early 

 stages in the detritus of old tree trunks. He found, in July, 1848, in a 

 deep wooded ravine near Charlottenbrunn, on the decaying trunk of 

 a tree of Fagus sylvatica, a newly hatched but already fully colored 

 specimen of Tabanus nigerrimus Zett., which had previously been 

 found in Sweden and Norway. 



Tahanus nigrescens Palisot de Beauvois. — This species is nearly 

 related to Tahanus stygius, occurring in the Atlantic States (New 

 Jersey), and also in Illinois. Of its oviposition nothing is known, 

 but Hart has observed the larva and given us a description of the 

 pupa. 



An undersized larva, supposed to belong with those of stygius, 

 pupated May 18, and on June 1 produced an imago of Tahanus 

 nigrescens. Most of the larvae, treated in Hart's paper as stygius 

 were very uniform in size and characteristics; Hart, though unable 

 to separate the two species at this stage, believes that the bulk of 

 his material at least was stygius. The imago of nigrescens had been 

 taken previously near the Mississippi, in southern Illinois, on 

 August 10. 



^ Pupa, Male. — Length 25 mm., diameter 5.5 mm. Palpal sheaths narrowly 

 separated, about one fourth as far apart as the setae borne by the large frontal 

 tubercles, a smooth depressed space between them, without tubercles. Lobes 

 of carinate transverse ridges of head more rounded and separated by a deeper 

 notch than usual. Abdomen a little more shining and more smoothly wrinkled. 

 Otherwise not different from the pupa of stygius (female) next described." 



From Malloch's analytical table the following data are obtained 

 on the pupa: 



"Pupa. — Dorsal abdominal segments, four to six at least, with one or two 

 transverse series of short irregular spines, the bases of which are not much dilated, 



