356 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



Packard (Report TJ. S. Geol. Surv., vol. 1878, p. 526), who gave an out- 

 line of the larva, and more fully in Bulletin No. 4 of this Bureau (pp. 

 28-29), where from a single rubbed female specimen of the moth we in- 

 dicated that it probably belonged to the genus Myelois. 4 number of 

 specimens of both sexes reared the past summer have permitted its 

 positive reference to the allied genus Acrobasis, of which it proves to be 

 a new species. 



Mr. Smith, in bis report which follows, has recorded some further ob- 

 servations on the habits of the species, and it is only necessary in this 

 connection to summarize the facts. 



The eggs, which, like typical Tortricid eggs, are flattened and con- 

 form more or less closely to the object to which they are attached, are 

 generally laid singly, and usually in the calyx of the forming fruit, 

 though sometimes on the surface of the young berry. As many as 

 a dozen may be laid in a single calyx, however, when, as with Tor- 

 tricid species, they often overlap each other. The larva works in the 

 heart of the berry, and goes from one to another, ruining from three to 

 four before attaining full growth, which is usually consentaneous with 

 the ripening of the fruit. It stops up the entrance hole with silken 

 web, and the affected berry turns prematurely red and finally shrivels 

 and drops. Pale at first, it becomes green (with more or less pink) with 

 age, and attains a length of about half an inch (Plate IX, Fig. 4, d). 



It is found of all sizes during autumn, and a few later specimens per- 

 sist till winter; but the bulk leave the ripening berries in September 

 and October, and enter the ground, where each hibernates in an ovoid 

 cocoon of silk, covered with grains of earth and sand (Plate IX, Fig. 

 4, g). The pupa (Plate IX, Fig. 4, e) is formed the following spring, and 

 the moths issue quite regularly during the month of June or by the 

 time the cranberries are forming. 



The arsenical mixtures carefully sprayed during June and July in 

 the manner already indicated in these reports, so as to reach the calyx 

 cavity, will prove the most satisfactory preventive of this insect's inju- 

 ries by killing the young larva as it attempts to eat its way into the 

 berry ; while experience would indicate that the natural growth of the 

 berry, together with the effect of summer rains, will rid the fruit, as it 

 matures, of whatever trace of the poison might prove injurious. 



DESCRIPTIVE. 



Acrobasis vaccinii n. sp. — General color and appearance of A. indiginella Zell. 

 (nebulo Walsh), but a somewhat smaller species, with primaries usually narrower. It 

 may be distinguished by the following differences as compared with indiginella : 



Average expanse, 15 mm . Colors of a colder gray, with less reddish-brown or tawny 

 on the inner portions of primaries, and with the pale costal parts nearly pure white, 

 so as to contrast more fully with the dark shades, and to more fully relieve the basal 

 branch of the forked shade on inner part of first or basal line, this basal branch be- 

 ing also usually darker than the outer or posterior branch. The triangular costal 

 patch from the basal line is obsolete. The transverse pale lines are less clearly de- 

 fined, and the terminal is nearer the posterior border of the wing, i. e., the median 

 field is wider. The geminate discal dots are always well separated, and the inner 

 one well relieved by the white which extends around it on the darker ground and 

 often forms an annulus. The oblique shade from apex is less clearly defined. 



Described from sixteen specimens of both sexes, reared from cranberries. 



Egg. — About 0.4 mra long and 0.3 mm broad, ovate or almost circular, and flattened or 

 plano-convex, the form varying with the surface of attachment, to which, while plas 

 tic, it partly conforms. Color olive-green or brown. 



Larva. — Average length when full grown 10 mm . Convex above, flattened beneath 

 Surface of body minutely granulate, with a dull somewhat greasy appearance. Color 

 varying from greenish-yellow to olive-green, reddish or brownish, being generally 

 darkest towards the anal end. Head yellow, polished, somewhat lighter towards the 



