54 



3 4 5 o 7 b 9 io ii 12 13 14 



» — > — » — , > > > ■ 



6|' 6f 7 ' 5 ' 5 4* 4 3 2 2' 2 2 3 

 15 16 



11' 



4' 24" 



The true lengths in mm. of these spines may be obtained by 

 multiplying the lower figures by .0035. 



On the cephalic region of the dorsum I have been unable to 

 distinguish a pair of spines to correspond with those in A vapora- 

 riorum as well as in the later instars of A. packardi itself. 



The length of the body in the first instar varies from .29 to 

 .35 mm., the greatest width from .16 to .18 mm. 



Second and Third Instars. In these stages the only difference 

 in structure observed between the two species is in the comparative 

 lengths of the first and third pairs of dorsal spines, the second pair 

 in both species being minute. In A. packardi all three pairs are in- 

 variably minute. 



The length of the body in the second instar varies from .41 to 

 .45 mm., the greatest width from .21 to .26 mm. 



The length of the body in the third instar varies from .56 to 

 .62 mm., the greatest width from .32 to .38 mm. 



Pupa. The most marked differences between the two species 

 are in the pupal stage, although at a casual glance they appear alike. 

 In A. packardi all three pairs of dorsal spines are minute, while in 

 A. vaporariorum the third pair is very variable in its degree of de- 

 velopment, as already described. In the former there is only a 

 double sub-marginal series of wax rods present, none arising farther 

 up on the dorsum. The rods of the outer series, unlike those of A. 

 vaporariorum, are very variable in length, in mature pupae being 

 usually more than one-half the width of the body in length. The 

 number of rods in the outer series averages much greater in A. pack- 

 ardi than in A. vaporariorum, there being from about sixty to one 

 hundred present in the former and from about fifty to seventy-five 

 in the latter species. The inner sub-marginal series of rods also 

 differs in number in the two species, there being eighteen or twenty 

 in A. packardi and but ten or twelve in A- vaporariorum. In both 

 species these (the inner-submarginal series) are usually directed up-, 

 ward and curved inward over the dorsum of the body, but the varia- 

 tion in their place of origin is much less in A. packardi, none having 



