FRIT1LLARIES. 



LIFE HISTORY. The EGGS are laid in the 

 months of May and June, on the leaves of 

 stinging - nettles (Urtica urens and Urtica 

 dioica), in batches of sixty or eighty, and some- 

 times a much larger number ; the females 

 which perform this duty having survived the 

 winter. The eggs are so much the colour of 

 the nettle-leaves that it is difficult to detect 

 them ; they are laid all in a lump, like a 

 bunch of grapes or a handful of gooseberries, 

 and as the late Dr. Maclean, of Colchester, 

 justly observed, have a very singular appear- 

 ance. Each egg is oblong, and depressed at 

 both extremities ; at the upper extremity is a 

 circular operculum, which is pushed off and 

 disappears at the time of hatching ; there are 

 generally eight longitudinal keels or ridges ex- 

 tending from the operculum to the base, but this 

 number is not constant, varying to seven and 

 nine. In an average period of fourteen days, 

 but varying according to the temperature, the 

 young CATERPILLARS emerge, and remaining in 

 company, spin together the leaves of the food- 

 plant : as they consume the leaves the limits 

 of their dwelling are extended, and they con- 

 tinue to live in company until fully half-grown; 

 they then separate, and each feeds alone. 

 When full-fed they rest in nearly a straight 

 position, but on being disturbed fall off the 

 food-plant, and lie in a curved posture, the 

 head and tail approaching. The head is wider 

 than the second segment, tut narrower than 

 those which follow; it is somewhat notched 

 on the crown, and is covered with spinose 

 points, which vary in size, and each of which 

 terminates in a bristle; the second segment is 

 narrow, and has a transverse series of small 

 spines, each of which terminates in a bristle ; 

 the third and fourth segments have each a 

 transverse series of eight spines two on each 

 side of the belly near the insertion of the leg, 

 very small and inconspicuous ; and two others 

 on each side of the back, conspicuous and 

 branched, each of the branches, as well as the 

 central spine, terminating in a bristle ; the 

 following segments, from the fifth to the 

 twelth inclusive, have each seven branched 

 spines, one medio-dorsal, the other at regular 

 intervals, the medio-dorsal spine always placed 



slightly in advance of the rest: the thirteenth 

 segment has four branched spines : the head 

 is black, its warts white : the body has the 

 dorsal surface black and irrorated with yellow 

 dots, each of which emits a slender bristle ; 

 these dots are frequently so numerous as to 

 form a broad yellow medio-dorsal stripe, which, 

 however, is always interrupted by a narrow 

 median black stripe : on each side are two 

 yellowish stripes, one above, the other below, 

 the spiracles ; the subspiracular stripe is the 

 brighter and more distinct of the two ; the 

 spiracles are black and surrounded by a pale 

 ring; the belly is pale, excepting between 

 each pair of claspers, where it is dark, but 

 still irrorated with minute white dots ; the 

 spines are generally smoky green, but not un- 

 frequently black ; the claspers are smoky 

 green. When full-fed the caterpillar fre- 

 quently crawls away from its food-plant, and 

 selects a twig or leaf of some neighbouring 

 plant, or the coping-stone of a wall, or a 

 wooden rail or palings, on which to undergo 

 its change to a chrysalis, but it more often 

 prefers the under side of a nettle-leaf; in 

 either case it spins a slight web over the 

 object selected, and, suspending itself there- 

 from by the anal claspers head downwards, it 

 becomes a rather elongate and sharply angu- 

 lated CHRYSALIS, which has the head deeply 

 notched on the crown, the points distant and 

 acute; the thorax is dorsally humped; the 

 hump having a median elevated point ; on 

 each side of the thorax, near the insertion of 

 the wing-cases, are two rather obtuse eleva- 

 tions ; the back has three series of raised 

 points, the median series consisting of six, aii 

 of them small and insignificant ; each taw>;-w* 

 series consists of nine points, three or them 

 thoracic, small and insignificant, the remain- 

 ing six conspicuous and abdominal ; the ter- 

 minal segment of the body is slightly spoon- 

 shaped, and terminates in a complete fringe 

 of minute hooks, by which the chrysalis is 

 attached to the web : the prevailing colour of 

 the chrysalis is brown, mottled or reticulated 

 with black, and adorned with golden spots 

 and reflexions ; the spots generally comprise 

 the lateral spinous processes; about the juno 



