INSECUTOR INSCITI^ MENSTRUUS 139 



Male. The palpi have the white scales predominating on 

 the shaft, the hairs of the last joints black. Abdomen marked 

 as in the female, with broad white basal bands, generally in- 

 dented centrally and with an apical triangle of pale scales, 

 often wholly pale dorsally with paired black spots. Wings 

 with the scales sparser than in the female, black, but showing 

 many white ones in the costal region. 



Hypopygium. Side pieces conical, about three times as long 

 as wide ; apical lobe nearly bare, with only a few very small 

 setae, which are turned outward, away from the face of the 

 lobe ; basal lobe flat, a long slender spine on the margin, ac- 

 companied by three or four setse about as long as it ; the re- 

 mainder of the lobe, which is rather large, bears very short 

 setae from slight tubercular bases. Claspette rather long, the 

 filament long, sickle-shaped, a little expanded at tip and longer 

 than the stem. Tenth sternites normal. Ninth tergites with 

 about ten stout spines. 



Larva. Head rounded, about as wide as long, darkly infus- 

 cated; antennae uniform, rather small, dark brown, the tuft a 

 little beyond the middle ; head hairs single, occasionally double, 

 the upper pair in one specimen triple. Air-tube about two- 

 and-a-half times as long as wide, dark brown, the 5- to 7-haired 

 tuft arising before the middle; pecten generally of few teeth 

 (9), variable, the terminal tooth often detached, but as often 

 not, frequently differing on the two sides of the same speci- 

 men. Anal segment with the dorsal plate reaching the middle 

 of the sides at the farthest, irregularly edged and narrower 

 behind. Lateral comb of the eighth segment of about twelve 

 large scales in two irregular rows, each scale with long central 

 thorn and stout short lateral spinules. 



The species seems a good one, allied to impiger Walker 

 (decticus H., D. & K.) and prodotes Dyar. It is nearest to the 

 former, but has adopted a desert dress as befits the open nature 

 of its habitat, the plains about the Great Salt Lake being 

 wholly devoid of any vegetation more than a foot high, except, 

 of course, as modified by cultivation. 



The mating habits have not been observed. 



