ECONOMIC ZOOLOGY — ENTOMOLOGY. 261 



jictive larva?, hut can merely squirm when irritated. The plowing, which should 

 be deep to be effective, turns out great numbers of these pupte, and they are either 

 eaten by birds or killed by the burning sun. Many more are destroyed by 

 being crushed or sufifocatetl in the broken pupal cells. Aside from killing many 

 PJleodes i)Up;e, this practice of late plowing the summer-fallow would greatly 

 tiid in weed eradication." 



The results obtained through treating the seed with lead arsenate at the rate 

 of 5 lb. per bushel, dissolved in water; strychnin sulphate, at the rate of 

 s oz. per bushel, dissolved in water; and coal tar applied until the seed was all 

 coated, then sanded until dry, were entirely negative, as all the plats, including 

 the checks, were about efjually attacked. 



Technical results from the gipsy moth parasite laboratory. — IV. The 

 chalcidoid genus Perilampus and its relations to the problem of parasite 

 introduction, II. S. SMrni {U. S. Dcpt. Agr., Bur. Ent. Jiiil. 1<), pt. .'/, tech. 

 «er., pp. 83-69, figs. 8). — Daring investigations in the spring of 1909 the author 

 found a first stage larva (for which type of larva Wheeler has suggested the 

 term " planidium ") of Perilampus hyalinus, in the larvse of Limnerium validum, 

 an important parasite of the fall webworm. Later an adult was reared from 

 a second planidium encountered in a pupa of the tachinid Varichwta aldrichi, 

 also an important enemy of the fall webworm. 



During the following fall sevend thousand young fall webworm caterpillars 

 were collected and reared to maturity. Apanteles hyphantria; Riley was foimd 

 to be a fairly common parasite of the younger caterpillars, and V. aldrichi and 

 L. validum of the older ones, as during the preceding summer. Examination 

 of the puparia and cocoons of the parasites disclosed the fact that the planidia 

 of Perilampus were even more common than they were during the preceding 

 year. Maggots of the tachinid which had emerged from the caterpillar were 

 examined and found to contain the planidia internally. " Dissection of the fully 

 develoix*d caterpillars revealed the fact that the tachinid maggots while still 

 within the caterpillar contained these planidia, and going back still further to 

 the younger caterpillars, the planidia were found to be present here irrespective 

 of whether the caterpillar was infested by a primary parasite or not. Exami- 

 nation of a considerable number of the Hyphantria caterpillars showed that the 

 planidium could be found in almost any portion of the caterpillar's anatomy, 

 although they generally ' floated about ' freely in the body cavity. Occa- 

 sionally specimens attached to the larval organs, such as the alimentary canal 

 or silk glands, were encountered. Further study of still younger caterpillars 

 revealed the most interesting and significant feature of the whole life cycle, 

 namely, the presence of the planidia upon the exterior of the caterpillars. These 

 were apparently about to make their way through the integument to the interior 

 in a search for suitable hosts uix)n which to complete their development.'" 



Just how these planidia came to be located upon the skin of the caterpillars 

 and how, when, and where the adult female Perilampus places her eggs, could 

 not be ascertained. It is suggested that either the eggs are deposited upon 

 ITbwer heads or upon leaves of plants not in the immediate vicinity of the cater- 

 pillar colony, the planidia hatching from these eggs and being conveyed to the 

 caterpillars by means of some intermediate carrier, or, which seems to be more 

 plausible, that the eggs are deposited upon the food plant in the vicinity of a 

 colony of the caterpillars. Dissection of adult female Perilampus indicated that 

 the eggs are very numerous, as high as 250 fully developed eggs being found 

 at one time. 



Once the planidium becomes afiixed to the caterpillar, it makes Its way 

 through the thinner portion of the integument found at the junctures of the 

 segments, this passage being effected by means of its well-developed mouth 



