HIE LARVA. 37 



Many larvae are destitute of eyes, namely, all maggots with an 

 undeveloped head, as well as many larvae with a distinct corneous 

 head-plate. The eyes of larvae are always simple, and perfectly agree 

 in form with those eyes of the perfect insect, with which we shall 

 become acquainted as ocelli. They are also placed in the vicinity of 

 the mouth, close behind the antennae (g, g) ; they vary in number 

 from one to six on each side ; but the caterpillars of butterflies appear 

 invariably to possess the latter number 



54. 



These, as well as the larvae of the saw-flies (Tenthredonodea and 

 Urocerata,) and those of the May-flies (Phryganeodea), possess, 

 attached to their maxillae, a peculiar organ, which Kirby and Spence 

 very aptly call a SPINNERET (fusulua, PL II. f. 14), which is of great 

 importance to them for the preparation of their cocoon. It originates 

 from the anterior portion of the labium, and is a slight tube, obliquely 

 truncated at its apex, and composed of several alternately corneous and 

 membranous slips. It is through this tube that the clammy liquid 

 passes, which has been secreted by two glandular organs for the pre- 

 paration of the silk, and which can be spun into thicker or thinner 

 filaments at the will of the caterpillar, by the power it possesses 

 of distending or contracting the cavity of the tube. The larvae of 

 some Coleoptera and Dictyoloptera, which also spin cocoons, do not, 

 however, possess this organ ; but the silk is produced by an apparatus 

 at the anus : a very different construction must consequently obtain 

 in them. 



55. 



The head is immediately succeeded by three segments, which ulti- 

 mately, in the perfect insect, form the thorax. They are recognised in 

 many larvae by the short, corneous, articulated and conical feet, which 

 are observed only upon these segments. In general they are con- 

 structed like the rest; but in the larvae of many Coleoptera, particularly 

 of the superior families, they are distinguished by a peculiar conforma- 

 tion ; their exterior integument is corneous, like that of the head, whilst 

 that of the abdomen is enclosed by a soft skin. Among the case or 

 caddis-worms also (Phycis, Phn/gaiiea}, which, as larvae, dwell in a 

 case made by themselves of sand and bits of stick, and wherein also 

 they transform themselves into pupa, a similar construction is percep- 

 tible (pi. III. f. 1). 



56. 



The LEGS (pcdes) of larvae take a different form, according to their 

 position 



