532 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



■worm. During the earlier part of the summer this insect was not very 

 numerous, but sufficient proofs in form of emx:»ty cocoons were ob- 

 served to indicate at least one earlier brood. Towards tlie end of Sep- 

 tember, and as late as the Inth of October, very numerous cocoons of 

 a second brood were formed; they could be found in all situations to 

 which the caterpillar itself had access. But the great majority of 

 them were suspended from the trunks* and branches of trees, and 

 chiefly from near the base of the trunk. Each represents the death 

 of one nearly full-grown caterpillar, since the latter harbors but one 

 larva of the parasite. A careful watch was kept to see how such 

 a suspended cocoon was formed, but in vain. Once a larva had just 

 started to make a cocoon, but became detached, and dropped out of 

 the orifice and commenced a new one. The larva, susj^ended by the 

 mandibles, evidently spins at first loose, irregular, horizontal loops 

 around its body, until a loose cradle is formed. The silk secreted for 

 this purpose hardens very rapidly when exposed to the air. When 

 secure inside this cradle it lets go its hold with the mandibles, and 

 finishes the soft inside cocoon in the usual manner. If the larva has 

 dropped to the ground, it still makes an outer loose cocoon, but the 

 silken threads are thicker and much more irregular. In cocoons 

 made during a high wind, the threads that suspend them are much 

 longer, reaching sometimes the length of 4 inches; the more normal 

 length varies from 1-^ to 2 inches. 



To find out the length of time which this insect occupies in matur- 

 ing inside the cocoon 44 freshly made cocoons were put in a glass jar. 

 With remarkable regularity, but ten days were consumed by the in- 

 sect in changing from the larval to the winged foi-m. The winged 

 Meteorus issues through a perfectly round hole at the lower end of 

 the cocoon by gnawing off and detaching a snugly fitting cap. The 

 several secondary parasites of the Meteorus which we have men- 

 tioned all leave the cocoon of their host by smaller holes cut through 

 the sides. Most of the adult Meteorus had issued by the 1st of No- 

 vember; but it is xoossible that some may remain in their cocoons until 

 spring. 



In order to obtain the proportion between the Meteorus raised from 

 cocoons and its parasites (^. e., secondary parasites of Hyphantria), 

 450 cocoons were confined in a glass jar the latter part of September. 

 Up to the first week in November only 70 specimens were bred from 

 these cocoons, the rest giving out secondary parasites, which con- 

 tinued to issue up to date of writing (December 20, 1880). Tims only 

 16 per cent, of the cocoons produced the primary, while 84 per cent. 

 produced secondary parasites. The>insect is new, and we submit the 

 following description: — 



Meteorus hyphantria n. sp. — 9 . Length, 5'""; expanse, 11""". Comes nearest 

 to Meteorus communis Cress. , being, however, a larger species. Its cocoons are also 

 larger and of a darker yellow-brown in color. General color, honey-yello^v^ The 

 irregular reticulation of the metanotum shows less tendency to arrange itself in 

 longitudinal carina?,, particularly into one median and two sublateral. The fine longi- 

 tudinal impressed aciculations of the first abdominal segment are nearly parallel in 

 hyphantrice, while in conuminis the middle ones c<;)nverge strongly towards the 

 center behind. The general color is, as in communis, yellowish-ferruginous or honey- 

 yellow. In general, hyphantrice has more dark markings than comviunis. The 

 antennge are dusky at tip; the mandibles are brown at tip; the mesoscutum has two 

 nearly black patches at sides and often a dusky stripe down middle; the metanotum 

 is usually entirely dark, as is also the first joint of the abdomen above; the rest of 

 the abdomen has two larger or smaller dark spots on each side; the sheaths of the 



* In one instance only, the cocoon* of this parasite was found inside that of its host. 



