THE BARNACLE SCALE. 59 



form of tho young, clotted over the glossy surfaces of the leaves, fre- 

 quently attract attention, but their numbers are always so greatly re- 

 duced (luring growth that only three or four per cent, rcii'-h tho 

 adult age. 



The thinning-out is not alone the work of enemies and parasites, bat is 

 also due to the fact that the lice, when they become gravid, cannot main 

 tain their hold upon the smooth surface of the leaves. Tbey fall to the 

 ground and perish, being in the latter portion of their lives incnpnbl" 

 of free movement and, therefore, unable to reascend the trees. T'.w 

 Orange is not, therefore, adapted to this species of Scale-insect, and is 

 never subject jlo long-continued or very damaging atticks by it. 



The occurrence of this Cark-louse upon wild plants, in portions of 

 Florida very remote from cultivation, seems to indica*:e that it is indigen- 

 ous, and not imported as supposed by Mr. Ashmead, who, however,con- 

 siders it identical with Ceroplastes rasci (Linn.), a common European 

 species. Professor Comstock, who has carefully compared tiie Ad 

 World species with our own, remarks that G. fioridensis "presents sev- 

 eral marked dilierences ; the most easily -noticeable being the small 

 size of the central plaie, and its entire disappearance so early in the life 

 .of the insect." 



Parasites. — A small Uymenopterous fly has been bred from Cero- 

 plastes floridensis. It is similar iii appearance and habits to Eneyrtus 

 Uavns Ilowanl, previously mentioned as preying upon Lemnium lies- 

 peridum* In his paper on parasites of the Ooccidte (Report Comm. 

 Agric. for 1S80, p. 3G9), Mr. Howard notices the occurrence of an allied 

 parasite, a species of tho genus Tetrastichus, which also remains uude- 

 scribed.^ 



THE BARNACLE SCALE. 



{Ceroplastes cirripediformls Comstock.) 

 [Fig. 21.] 



The following account of this somewhat uncommon scale is given by 

 Professor Comstock (Report Commissioner of Agriculture for 1880, 

 p. 333): 



"AdM/fjPcwfl/c— Average length 5'""'; width, 4™*"; height, 4'"'°. When 

 naked the color is dark reddish brown; the shape sub-globular, with a 

 strong spine-like projection at the anal end of the body. The waxy 

 covering is dirty white, mottled with several shades of grayish or light 

 brown, and even in the oldest specimens retains the division into plates, 

 although the form i.s more rounded and the dividing lines by no means 

 as distinct as at an earlier age. There are visible a large convex dorsal 

 plate, and apparently .six lateral, each with a central nucleus; the anal 



* This may bo AphijcuH ccropla^tia Ilowanl, described iu UuUctiu 5, Bureau of Ea- 

 tomology, as bred lioui Ceroplastea artemeave Riley MSS., from Silver City, N. Mox. 



