STEUCTURE, DEVELOPMENT, AND BIONOMICS OF HOUSE-FLY. 367 
1. Ch ernes nodes us Schrank. 
Thei’e are frequently found attached to tlie legs of the 
house-fly small scorpion or lobster-like creatures which are 
Arachnids belonging to the order Pseu do-scorpi oni dea; 
the term “chelifers^’ is also applied to them on account of the 
large pair of chelate appendages which they bear. The 
species which is usually found attached to M. domes tic a is 
Cher lies iiodosus Schrank (fig. 13). It is very widely 
distributed, and my observations agree with those of Pickard- 
Cambridge (1892), who has described the group. 
The species is 2‘5 mm. in length and Pickard-Caiubridges’s 
description of it is as follows : 
“ Cephalothorax and pal[)i yellowish red-brown, the former 
rather duller than tlie latter. Abdominal segments yellow- 
brown ; legs paler. The caput and first segment of the 
thorax are of equal width (fi-om back to froiit) ; the second 
segment of the thorax is very narrow. The surface of 
the cephalothorax and abdominal segments is very finely 
shagreeued, the latter granulose on the sides. The hairs on 
this part as well as on the palpi and abdomen are simple, but 
obtuse. The palpi are rather short and strong. 'I’lie axillary 
joint is considerably and somewhat subcouically protuberant 
above as well as protuberant near its base underneath. The 
humeral joint at its widest part, behind, is consideiably 
less broad than long ; the cubital joint is very tumid on its 
inner side ■, the bulb of the pincers is distinctly longer, to the 
base of the fixed claw, than its width behind ; and the claws 
are slightly curved and equal to tlie bulb in length.” 
They appear to be commoner in some years than in others. 
Godfrey (1909) says: “The ordinary habitat of Ch. nod os us, 
as Mr. Wallis Kew has pointed out to me, appears to be among 
refuse, that is, accumulations of decaying vegetation, manure- 
heaps, frames and hot-beds in gardens. He i-efers to its occur- 
rence in a manure-heap in the open air at Lille, and draws my 
attention to its abundance in a melon-frame near Hastings in 
1898, where it Avas found by Mr. W. 11. Butterfield.” In 
