202 



THE AMERICAN 



audintliis instance the rate of consumption was 

 about tlie same, two caterpillars a day for each 

 of these little creatures. The second time I fed 

 them thejr did not get though their work quite 

 so quickly ; possibly they may have overfed 

 themselves at first. 



While turning up the brauches of some of 

 my gooseberry bushes, I obsei"ved a number of 

 whitish eggs on some of the leaves, arranged 

 lengthwise in regular rows at short distances 

 apart, on the principal veins or ribs of the leaf. 

 Usually they were placed singly in the rows, but 

 here and there double. These were the eggs of 

 the currant worm, they were about one twentieth 

 of an inch long, four times as long as broad, 

 rounded at each end with a whitish glossy sur- 

 face. On the branch I was examining there were 

 three leaves with these eggs on ; two of them had 

 their principal veins pretty well covered, while 

 the third had but a few on it, as if this had been 

 the work of a single insect which had exhausted 

 her stock before the third leaf was covered. 1 

 counted these, and found there were 101 in all. 

 Having just then caught one of the parent flies, 

 a female which was hoveriiig about as if look- 

 ing for a place on wliich to deposit her eggs, I 

 squeezed some eggs out of her bod)' and com- 

 paring them with those on the leaf, found they 

 were only about half the size, showing that the 

 first must have grown considerably after being- 

 laid and that they were probably nearly ready to 

 hatch. In about three hours afterwards, 1 ob- 

 sei'ved that several of the young larvas had come 

 out of the eggs, and placing the leaf under a 

 microscope had the good fortune to see some of 

 them escape. The egg consisted of a thin elastic 

 ^ memljvane sufficiently transparent to give a dim 

 A'iew of tlic enclosed larva. The black spot 

 which is placed on each side of the head in this 

 species, enabled me to determine the position the 

 creature occupied. It was somewhat coiled up 

 and resting on its side Avitli its jaws against the 

 side of the egg not lar tVoni ils extremity. I 

 could not perceive that it litid any other means of 

 rupturing the egg than by its mandibles, which 

 were working visibly within. In a short time 

 tlie egg was ruptured and the head of the larva 

 protruded from the orifice. AVithdrawiug its 

 two front feet from the egg, it seized the leaf on 

 which it was placed, and by raksing up its back 

 and working itself from side to side, it soon 

 woi'ked itself out. The time occupied in thus 

 extracting itself, from the first appearance of the 

 head, varied from six to ten minutes, for I 

 watched several of them through the process. 

 The egg was so thin and elastic that it yielded 

 readily to the motions of the body, and adhered 



very closely to it, contracting and slirivelling up 

 as the body was withdrawn. 



After the lai-va comes out it does not consume 

 the egg or any portion of it, as is the case with 

 most Lepidoptera, but sets to work at once eatr 

 ing the leaf on wluch its considerate mother 

 placed it. When just hatched the worijis are 

 about one-twelfth of an inch long ; head large, 

 dull whitish with a round dark spot on each 

 side, and a few minute short hairs ; mandibles 

 pale brown. Body above and below whitish, 

 semi-transparent, sometimes with a slight green- 

 ish tinge. From this time it rapidly increases 

 in size, becoming green then changing to green 

 with many black dots, and finally reverting to 

 pale green again, tinged with yellow at the 

 extremities, just before it becomes a chrysalis. 



I have a fact to communicate regarding the 

 winter history of this insect. It has been uni- 

 versally held, that the larvse, when they leave 

 the bushes in the fall, at once construct their 

 cocoons, either at the surface of the ground or 

 just below the surface, and change to pup£e 

 either then or sometime before early spring. 

 Possibly as a rule this may be the case, if so 1 

 have an interesting exception to record. On the 

 22nd of May I was trying some experiments in 

 crossing gooseberries, fertilizing the flowers of 

 the Houghton's Seedling with some of the large 

 English varieties, and having operated on several 

 branches, tied them up in new paper bags to 

 prevent interference with the work, either from 

 insects or otherwise. The particular bag 1 am 

 about to refer to, was attached to an upright 

 branch on the summit of the bush, about eight- 

 een inches from the ground. Wliile examining 

 it on May Hist, nine days afterwards, to ascer- 

 tain the resiTlt of my work, I found in one of the 

 folds of the bag a cocoon of N'emanius ventri- 

 cosvs firmly attached to the paper. In tliis in- 

 stance the larva must have remained unchanged 

 during the winter, then crawled from the ground, 

 attaching itself as related and constructing its 

 cocoon after the 22d of May. A few days later, 

 I found a sinular cocoon attached to the bush, 

 which from its fresh appearance I inferred had 

 been constructed about the same time, although 

 I am unable to advance any jjositive statement 

 regarding it. During the sunmier I have found 

 a considerable number of siich cocoons fastened 

 to the underside of the leaves of the bushes on 

 which the larvas have been feeding, and these 

 have been observed in all positions from near 

 the base to the summit of the bushes, showing 

 that it is not the invai'iable practice of the larva 

 to undergo its change to chrysalis, either at the 

 surfoce or under the surface of the ground. 



