THE CHIRONOMIDA. 173 
The alimentary canal can be seen through the body-wall, and 
consists of the following parts: cesophagus, proventriculus, stomach, 
and intestine. 
There is another curious larva C. stercorarius described by Walker,* 
I have not had the opportunity of examining the species myself: 
“ The grub of C. (Orthocladius) stercorarius inhabits horse-dung, and 
has a fleshy leg on the under side of the first segment, which points 
towards the head, and which it has the power of lengthening and 
contracting. Its various serpentine contortions also assist it in 
moving. When removed from the substance which constitutes its 
food, it is enabled to regain it by leaping. Lying horizontally, it 
brings the anus near the head, regulating the distance by the length 
of the leap it means to take; when, fixing it firmly, and then 
suddenly resuming a rectilinear position, it is carried through the air 
sometimes to the distance of two or three inches. It appears to 
have the power of flattening the anal extremity, and even of render- 
ing it concave, by means of which it may probably act as a sucker, 
and so be more firmly fixable.” 
From the mention of only gve fleshy leg, I should imagine this 
description is taken from an immature larva. C. p/umosus and others, 
when quite young, show that the wo prolegs arise from a cleft down 
the centre of a single protuberance. This point is well shown in 
Grumm’s figures of the species he made observations upon; he 
says: ‘‘ The thorax on its ventral surface possesses a transverse fold, 
which is divided in the middle by a deep furrow, and transformed 
into a pair of clinging feet.” There is little doubt that the single 
proleg of stercorarius described by Walker is accountable for in this 
way. The larve of Zanypus are built much upon the same type, 
some living in stagnant water (Z. maculatus), others in swampy 
places, upon various water-weeds (Z. monilis) almost as thin as a 
hair. 
Pedogenesis in Chironomus. 
M. Oscar v. Grumm found that agamic reproduction takes place 
amongst the Chironimi, and observed it fully in one species, and also 
the development from the unfecundated egg. The larvz which this 
observer experimented with were clear and transparent, of a 
yellowish tinge, with large head, a broad thorax, and 9-jointed 
abdomen. The mouth armed with two pairs of strong jaws, the 
lower forming an immovable lip. The thoracic part on its ventral 
surface possessed a transverse fold, which is divided in the middle by 
a deep furrow ; these eventually grow forward and form a pair of 
* Ins. Brit., vol. iii., p. 151. 
