30 THE CANADIAN ENTOMOLOGIST. 



Second Instar. 

 In this instar the form is more variable than in the first ; broadly oval 

 to elliptical, usually with a slight incurving on each side of the thoracic 

 region. When oval, the anterior end is the more broadly rounded. The 

 margin is finely crenulate, but there is no thin marginal rim as in the first 

 instar. Immediately after moulting, the body is flat and thin, but before 

 the next moult it becomes well rounded above. Three pairs of marginal 

 spines are present: the first pair on the latero-cephalic region, one on each 

 side ; the second pair on caudo-lateral region, one on each side ; and 

 the third pair on the caudal margin. These probably represent spines 

 number one, fourteen and sixteen, respectively, of the first instar. The 

 third pair is a little more than one-tenth the length of the body, the 

 second pair is about one-fourth the length of the third pair, and the first 

 pair is even smaller than the second pair and may be difficult to distin- 

 guish. There are three pairs of minute dorsal spines : the first pair is on 

 the cephalic region, one on each side of the middle ; the second pair is 

 on the first abdominal segment, one on each side; and the third pair 

 is near the vasiform orifice, one on each side, opposite the operculum. 

 These last are somewhat larger than the first and second pairs, which in 

 some specimens may be difficult to distinguish. They are most readily 

 seen immediately after the insect has moulted. A marginal wax secretion 

 is present as in the first instar, appearing shortly after the moult. The 

 segmentation of the abdomen is fairly distinct in the middle, that of the 

 thorax more obscure. The vasiform orifice is relatively farther forward in 

 this instar than in the preceding one. This is indicated by the com- 

 paratively greater distance from the apex of the orifice to the caudal 

 margin of the body and by the fact that the spines on the dorsum, near 

 the orifice, now lie opposite the operculum, instead of anterior to it, as in 

 the first instar. The vasiform orifice is of about the same general form 

 as in the first instar. The lingula is spatulate with two pairs of side lobes 

 arid one terminal lobe. On each side of the terminal lobe arises a seta 

 or spine about one-half as long as the entire vasiform orifice. Between 

 the two pairs of side lobes on each side a smaller spine arises. The 

 upper surface of the lingula bears longitudinal rows of minute setae, as in 

 the previous instar. When in its natural position, the lingula reaches 

 nearly to the apex of the orifice. The chitinous ridges which bound the 

 orifice laterally do not meet behind, though the intervening space between 

 them is comparatively smaller than in the previous instar. The eyes are 



