658 EXPERIMENT STATION RECORD. 



The moths emerge from the cocoons at or near the surfiice of the gi-onud 

 during the daytime in the latter part of May and in early June. During the 

 day they remain quietly on the bark of the trunk and larger branches, none be- 

 ing found on the leaves. Several huiKlred moths are often found on a single 

 tree; when disturbed they suddenly take flight and most of them settle on the 

 opposite side of the tree. They gradually decrease in numbers and about the 

 middle of June they disappear. 



The act of egg-laying has not been observed, but is thought to take place in 

 the evening or at night, as the moths are rarely seen on the leaves during the 

 day. The eggs are attached to the undersurface of the leaves, usually at the 

 forks of the more prominent veins. " The exact time required for the hatch- 

 ing of the eggs has not been determined, but it can not be far from 2 weeks. 

 On June 2, 1908, an examination of the orchard showed that a gi-eat number of 

 eggs had been laid ; on June 9 no eggs had hatched, and on June 18 hatching 

 had just nicely begun. 



" In hatching, the larva eats its way out of the eggshell on the underside 

 next to the leaf, and enters the leaf directly without coming out on the surface. 

 This is a point of great practical importance, as showing the futility of attempt- 

 ing to kill the larvc^e with an arsenical spray. When full grown the larva is 

 about i in. in length, greenish white in color with the head light brown. . . . 

 When full grown the larva leaves the mine through a cut in the upper surface 

 of the leaf, falls to the ground, and there constructs a small flattened brownish 

 cocoon in cracks in the soil, under loose stones, or between the base of the tree 

 and the surrounding soil. Where the gi'ound is undisturbed, the cocoons are 

 rarely found more than an inch below the surface. Sod furnishes ideal winter 

 quarters for the cocoons. . . . After forming the cocoon the larva appar- 

 ently does not transform at once ; a cocoon opened August 4, 1908, contained a 

 larva. The winter, however, is passed in the pupal stage. On October 10, 

 1011, the writer opened a number of freshly gathered cocoons and found that 

 all the larvae had transformed to pupte." 



A chalcidid parasite (Derostenus salutaris) has increased in abundance to 

 such an extent that in the fall of 1911 nearly one-half of the cocoons examined 

 were infested. The genus Nepticula to which this leaf-miner belongs contains 

 over 40 species from the United States and over 70 species are known to occur 

 in the British Isles. The larvae of all species of this genus so far as known 

 are leaf-miners, feeding within the leaf just below the upper epidermis. As a 

 rule each species is confined to a particular food plant, or at most to 2 or 3 

 closely related food plants. 



A list of the American si:»ecies of Nepticula. together with their food plants 

 Is given, as is a brief account of the European plum leiif-miner (Nepticula 

 plagicolella), a closely related form. 



" The plum leaf-miner has proved to be a difficult insect to control, owing to 

 the fact that from the time the larva leaves the egg it feeds entirely within the 

 leaf out of reach of any poison spray. Measures directed against the moths, 

 eggs, and larvae have all proved failures, and only partial success has been 

 attained by thorough cultivation to destroy the larvae and pupae in their 

 cocoons." 



The structure of certain dipterous larvae with particular reference to 

 those in human foods, N. Banks (U. 8. Dept. Affr., Bur. Ent. Bui. 22, tech. 

 ser., pp. 44, pis. 8, fig. 1). — The author here presents the results of a study 

 made of the structure of certain dipterous larvse that may be suspected or concerned 

 in internal myiasis. The bulletin first discusses the occurrence of and manner in 

 which dipterous larvae may be ingested, the life history of these flies, their 

 classification, and general characters, with a synopsis of the groups concerned. 



