18 BULLETIN 438, U. S. DEPABTMENT OF AGRICULTTJIIE. 



were found in May, 1914, indicating the probable existence of a 

 parasite. In the spring of 1915 the possibility of securing parasites 

 was kept in mind. On April 1 three small parasites were found in 

 one of the rearing jars, evidently coming from a single cocoon that 

 had a small hole in it. The following day the sawflies began emerg- 

 ing, and continued to do so until April 13. At this time there were 

 still over a hundred cocoons in the jars, and these were kept for 

 possible parasites. 



On April 24 a small ichneumonid, determined by Mr. S. A. Rohwer, 

 of the Bureau of Entomology, as Mesoleius sp., emerged from one of 

 the cocoons through quite a large hole that it had made. 



On May 4, 27 specimens of the small parasite previously referred 

 to were found in one of the rearing jars, having come from four 

 different cocoons, and in another jar 15 specimens of the same species 

 had emerged from three cocoons, or an average of 6 parasites for 

 each cocoon. These parasites, evidently chalcidids, have not been 

 determined. 



On May 19 a smgle larger parasite was found, which, upon being 

 submitted to Mr. S. A. Rohwer, proved to be a chrysidid, probably 

 Cleptes provancJieri Aaron. 



Thus it appears that of 308 cocoons, only 10, or a little over 3 

 per cent, were parasitized. The ravages of the sawfly would not be 

 diminished to any appreciable extent by this degree of parasitism, 

 though there may be years when these parasites are much more 

 numerous. It is interesting to note that practically all of these 

 parasites came out considerably later than the adult sawflies, and 

 at about the time when the largest number of sawfly larvae were 

 full grown. This indicates that the parasites oviposit on the larvae, 

 which is probably the case, as it is difiicult to understand how they 

 could reach the larvae after the latter had spim their cocoons in the 

 soil. Since there is but one brood of the host, there would be only a 

 single brood of the parasites if pecuhar to this host. 



In California larvae of coocinellid beetles in rare instances have 

 been observed to prey on the larvae of the pear sawfly. Before the 

 first of May coccinellid larvae are comparatively scarce, and so it is 

 unlikely that they will ever prove a check upon the pear sawfly. 



REMEDIAL MEASURES. 



The pear leaf-worm is easily controlled when in the larval stage. 

 A poison spray, such as arsenate of lead, if properly applied, is 

 highly effective (PI. II, fig. 1), because of the habit possessed by this 

 insect of passing the whole period of this stage of its life upon the same 

 leaf, unless forced to move away by interference, accident, or scarcity of 

 food, mainly due to the location of several larvae on one leaf and the 

 fact that they consume it before they attain the stage of pupation. 



