Annual Address of V. T. Chambers, Esq, 79 



and tempertiture, hastening or retarding the metamorphoses of the 

 species; and that there is a regular ratio between the quantities of food 

 consumed in the several stages of the same larvte; and another differ- 

 ent ratio between the rates of growth in the several stages. These 

 conclusions are indicated I think by such instances as I have already- 

 cited, and are more fully establislied bj' observations on the life his- 

 tories of the species of LithocoUetis now to be given. 



The genus LithocoUetis, as defined b}' Zeller, comprises numerous 

 species of small moths, gaily ornamented with spots and marks, usual]}' 

 of silvery white, upon a ground color of gold, saffron, or reddish orange. 

 The}^ are veiy small, rarely if ever reaching a body -length of l-3d of an 

 inch, and agree \evy closely in form and structure with each other, so 

 that it is impossible to separate them into an}^ well defined sub-genera 

 or group. The larvae are, without exception, what are known as leaf 

 miners ; that is, they mine or burrow in the parenchyma of leaves ; 

 and each species feeds only in the leaves of a single species of plant, 

 or at most in a very few closely related species, and very few if any 

 ti ue species are known, the larvae of which feed in leaves of plants that 

 are not closely related to each otlier. Unlike the moths, the larvae fall 

 readily into three distinct groups, known as the flat larvae, the ornatella 

 larvffi, and the CTlindrical larvae. The character of the flat group is 

 given in the name of the group; thej' are greatly flattened, with the 

 sides of the segments somewhat mamilated; and on top or bottom of 

 most of the segments of the body, and sometimes on both surfaces is 

 a macula, that is a spot or ring of darker hue than the remainder of 

 the body. From each side of each segment of the body project three 

 hairs, and just above these on the sides are two others. Their feet, 

 both thoracic and ventral, ai-e membraneous, and are not armed either 

 with the claw, which is usually found on the thoracic feet of caterpil- 

 lars, or the circlet of tentacles, which usuall}^ arm the ventral feet. 

 Their mouth parts, and form of the head, are represented at figure 1, 

 and the mouth parts more highly magnified are shown at figure 2. 

 The}' consist of the labium, which is divided into an upper and lower 

 lobe (« lower, h upper), but while the mouth parts, or as they are 

 technicall}' termed, the trophi, remain of this form, no labial palpi can 

 be discovered ; the maxillae (e), or lower jaw, are placed just above 

 the labium, uniting to form the floor of the mouth, but there are no 

 maxillary palpi, unless they are represented by the small organs (rf); 

 then there are the mandibles (e); and tlie spinneret (/), which extends 

 along the surface of the labium beneath the floor formed b}-^ the united 

 maxillte. This form of trophi lasts until the 5th moult, after which the 



