ELM LEAF BEETLE AND WHITE-MARKED TUSSOCK MOTH 9 



in size, following molts, is accompanied by the stiff hairs be- 

 coming less conspicuous and the yellow more prominent, till 

 the grub becomes full grown [pi. i, fig. 3]. It is then about one- 

 half of an inch long, more flattened than in the earlier stages, 

 with a broad, yellowish stripe down the middle of the back and 

 with a narrower stripe of the same color on each side, these be- 

 ing separated by broad, dark bands thickly set with tubercles 

 bearing short, dark colored hairs. The dorsal yellow stripe is 

 broken on each side by a subdorsal row of black tubercles which 

 decrease in size posteriorly. The lateral yellow stripe includes 

 a row of prominent tubercles with dark tips bearing hairs of the 

 same color. The under surface is yellowish. 



The pupa [pi. i, fig. 4] is a bright orange-yellow, about one- 

 fifth of an inch long and with a very convex dorsal surface 

 which bears transverse ro-ws of stout, inconspicuous hairs. 



Life history. The transformations of this insect are so rapid 

 and so greatly influenced by local conditions that a man must 

 know what to expect or he will accomplish very little in fighting 

 the pest, because a substance effective against the beetles or grubs 

 may not kill the pupae and, after the larvae have begun to de- 

 scend, may be of no value. The beetles winter in attics, sheds, 

 belfries and other shelters. They emerge with the advent of 

 warm weather and may then be found on the walks during the 

 sunny portion of the day or at the windows of houses, trying to 

 escape. The last of April or early in May, with the appearance 

 of the foliage, the beetles fly to the elms and eat irregular holes 

 in the leaves. Some time is occupied in feeding before the 

 deposition of eggs, the latter may continue four and possibly 

 five or six weeks. The prolific beetles consume a large amount 

 of foliage during this time, depositing clusters of from three to 

 twenty-six or more eggs every day or two. Over half the total 

 number of eggs may be laid at the height of the season within 

 about twelve days; in 1898, from June 12th to 23d. A female 

 may produce over six hundred eggs. 



The young grubs appear early in June or about five or six 

 days after the eggs have been deposited later in the season. They 

 feed on the under surface of the leaf, producing the familiar 

 skeletonization [pi. i, fig. 7] which is caused by their eating 

 the softer underpart. leaving the veins and the upper epidermis 

 practically untouched. The results of their feeding are so 

 marked that it is easy to detect the presence of the grubs by the 



