188 . MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
The galleries of the larvae are flattened, usually oval in cross section 
and winding, eradually enlarging as the larva increases in size. Pupa- 
tion occurs In a widened cell at the end of the larval mine. These 
larval mines are always tightly packed with fine sawdustlike pellets or 
frass arranged in arclike lay ers, and the surface of the wood in the 
burrow is scarred with fine transverse concentric lines produced by the 
mandibles of the larva. The beetles on emerging through the bark 
or the wood leave very characteristic oval or elliptical exit holes which 
can hardly be mistaken for the work of any other group of insects. 
The life cycle may be completed in part of one season, or may 
extend over several years in the case of the large stump borers. Some 
forms complete their development in the late summer, transform to 
adults, and hibernate in the pupal cells over winter. Some of the so- 
called bark-boring forms, as Agrilus and Melanophila, pupate in the 
bark or in the outer wood, depending on the thickness of the bark. 
Some species, such as those of Agrilus and Eupristocerus, work pri- 
marily in the small twigs. These often cause galls, and some of the 
species of Agri/us are twig pruners. Certain forms attack blazes or 
scars on living trees, and mine the sap or heartwood beneath; thus 
they prevent healing and even cause an extension of the injury. A 
few are cone borers, while others are leaf miners, spending the entire 
period of their development in the leaves, where they construct the 
pupal cell, and several bore in the stems of herbaceous plants. 
KEY TO THE ADULTS OF THE EASTERN GENERA OF BUPRESTIDAE 
he Hind coxal plates scarcely widened internally___________________ 2 
Hind coxal plates distinctly widened internally, front margin 
Straight -hind, marein obliques] 52 = =e ee 10 
2. rothorax truncate at base__________- ee saa e ws eS 3 
Prothorax: lobed:at bases. eS ee eee 5 
3. Mesosternum scarcely visible; breeds in small branches of oak 
Mastogenius Lee. and Horn 
Mesosternum,emareinate: < 242-2 a2 a eee ee ee 4 
4. Seute lenny: Wry has teeny ya ee ee Acmaeodera Esch. 
Scutellumy: plamly-indicateds = ys ae ee eee Ptosima Sol. 
5. Antennae not received in grooves on under side a prothorax 2.2. 2. 6 
Antennae received in grooves on under side of prothorax________ 7 
6. First joint of hind tarsi scarcely elongate; gall formers on alder 
Eupristocerus Deyr. 
First joint of hind tarsi as long as 3 following joints 
Agrilus Steph. 
fe ‘Earsi over half as long as tiblae222_] 3. 2 se Paragrilus Saund. 
Tarsi much shorter than tibiae 32 a ee 8 
8. Scutellum large: larvae leaf miners in certain leguminous plants 
Pachyschelus Sol. 
Scutellumsmall. 22.2 3 2 Se OE ee ee 9 
9. Prosternum with posterior cavity; larvae leaf miners in various 
Species; Of 08k 3222 a2 he eee eee eee Brachys Sol. 
Prosternum without cavity; leaf miners in Scirpius and other allied 
plantsa = =ee a ae Shel SE SS Ee Taphrocerus Sol. 
10. Antennal pores scattered on both faces of serrate JONES = ee 11 
Antennal pores concentrated in pits on these joints______________ 12 
Hil Apical third of elytral margin entire, or finely serrate; borers in 
pine'stumps and loge. elem) uae eee Chalcophora Sol. 
Apical third of ely tral. margins strongly serrate; borers in hardwood 
trunks Sate of Se eae eae ne eee ee Chalcophorella Kerr. 
12. Front not narrowed at insertion of antennae; eyes scarcely ap- 
proaching. often) distant on vertex. 2-60 = eee 13 
Front narrowed at insertion of antennae; eyes oblique, close 
together on vertex .2 22552 22. 4c i ee ee 21 
