38 



how far the insects ^y. Their structure indicates that the}^ are strong 

 fliers and capable, with favoring winds, of migrating considera))le 

 distances; but under ordinar}' circumstances they proba]>ly do not fly 

 many miles at a time or in a given year. 



THE ACORN MOTH. 



{Holcocera glandulella Riley.) 



In connection witli a consideration of the nut weevils a few words 

 should be said in regard to the acorn moth, a Tineid whose caterpillar 

 develops in nuts and acorns, usually in the deserted holes of the Bal- 

 aninus weevils. 



The adult, or moth, is variable in color, but is more or less ashy 

 gray, the forewings being characterized by transverse pale stripes 

 which are not specially well shown in the illustration, but which will 

 answer for present purposes. The moths vary in size as well as 



in mottling, the average ex- 

 panse of the forewings being 

 a little less than three-fourths 

 of an inch (see fig. 12, /"). 

 The moth, proper! y mounted, 

 looks decidedly wider than as 

 figured. The life history of 

 this species was long ago de- 

 scribed by Riley in his Fourth 

 Missouri Report (pp. 144, 

 145). After the weevil, which 

 was the original inhabitant of 

 the nut or acorn, has deserted 

 its temporary tenement, the 

 moth drops an egg into the already injured nut. The caterpillar hatch- 

 ing from this ^.gg develops upon what has been left by the larval nut 

 weevil, meanwhile securing the opening formed by the beetle with a 

 covering of silk to prevent the entrance of natural enemies. Farmers 

 who grow nuts as a side issue and who do not make a special stud}" of 

 the insects afi^ecting their acorns or other nuts are often prone to the 

 opinion that the true nut depredator is the caterpillar inclosed in these 

 nuts after they have fallen and been left on the ground. 



The acorn moth caterpillar has been described as pinkish-yellowish 

 or gra3nsh-white. Its recognition is facilitated by the illustration, a 

 showing the larva within the nut, and h the closed exit hole. There is 

 no difliculty in distinguishing- this caterpillar from the weevil larva or 

 grub, as it has, like most common caterpillars, a complete complement 

 of three pairs of legs and ten false legs. Within the nut it changes 

 to the chr^^salis stage, and the moth issues through the door. The 

 moths appear from April until September. Whether or not this 



Fl 



VI.— Holcocera f/lavduldla: a, acorn showing larva 

 at work; 6, acorn showing closed exit hole; c, head and 

 thoracic segments of larva; d, a lateral segment of 

 larva; c, a dorsal segment; /, moth; r/, base of antenna; 

 a, h, natural size; r, g, much enlarged; /, slightly en- 

 larged (after Riley). 



