EXPERIMENT STATION BULLETINS. 



239 



THE LARGE PEACH LECANIUM. 



(Lecanium sp.) 



A Lecanium on peach, the name of which has, as yet, not been determined, was 

 sent the writer on May lGth, from Michigan. It was also found by the writer in 

 another part of the State later. In the middle of May, the large females were full grown 

 but still soft and no eggs had as yet been deposited. 



The females of this species are clear deep brown in color, polished, with a liberal 

 covering of flocculent cottony material. They measure from one-fourth to five- 

 sixteenths of an inch in length, when full grown, sometimes a little more; from three- 

 -ixteenths to seven-thirty-seconds in breadth ; and about one-eighth of an inch in 

 elevation. The highest elevation occurs about one-third the distance from the anterior 

 margin, at which point the breadth is also the greatest, there being on each side a 

 rounded swelling from which there is a gradual slope to the posterior margin, and a 

 more abrupt slope to the anterior margin. The space beneath the anal scales and in 

 the anal fissure is often filled with white cottony material such as is found later with 

 the eggs. The edges of the scale on the sides pass down to the supporting bark 

 perpendicularly, flaring little or not at all. In front and behind the angle is necessarily 

 more acute but even here there is little, if any, flare. The surface is smooth and 

 polished, covered, except on the elevated swellings with a coat of pruinose material. 

 The pink eggs are laid about the last of May. 



Fig. 7.— Large Peach Lecanium. Adult females enlarged 4% times from photograph. Original. 



A microscopic examination shows the derm to be sprinkled with small more or less 

 circular spots, each spot having a smaller round area, apparently on the surface of the 

 derm. It is probable that these are the openings of the glands that produce the 

 pruinose material. They are more numerous and larger in the anal region than else- 

 where. The antennae usually are six jointed, though sometimes they are seven jointed. 

 There is a very great diversity of form in the different specimens at hand, those of a 

 single individual often being quite different. There is, however, a type to which many 

 of the individuals conform and which may be taken as the normal condition subject to 

 great variation in different individuals. In the typical form the second joint is 

 elongated, about as long as three, four and five taken together; joint one comes next, 

 then six. and then three, four and five, which are sub-equal. Joint six varies consider- 

 ably in length and sometimes joint three is elongated. 



The orchard from which these scales came was not badly infested, but they were scat- 

 tered about, a few in a place. No particular damage was sustained. 



The hymenopterous parasite Blastothrix longipennis, was bred from specimens of 

 this scale." 



D.C 



Kindiv determined for me by Dr. L. O. Howard, of the Department of Agriculture, Washington, 



n 



