24 ENTOMOLOGICAL SOCIETY 



America, also in Mexico, and in the eastern hemisphere, in 

 Ceylon, the Malay peninsula, Sumatra, Java, and also in parts 

 of Australia. 



Mr. Schwarz presented the following, illustrating his re 

 marks by sketches and exhibition of specimens : 



NOTE ON THE OVIPOSITOR OF SOME SPECIES OF 

 DONACIA. 



By E. A. SCHWARZ. 



While arranging a collection of North American Donacias I 

 noticed that in many females of the subgenus Plateumaris 

 (Group D of Mr. Leng's Synopsis of the Donacice of Boreal 

 America, in Trans. Am. Ent. Soc., xviii, pp. 159 ft'.) the 

 ovipositor is protruded and represents a very conspicuous object. 

 In the typical Donacia the ovipositor is never visible, and upon 

 dissection it was found that in these species the outer, hornv 

 sheaths of the ovipositor are but little developed and not capable 

 of protrusion. 



In the species of Plateumaris the outer sheaths of the ovipositor 

 form two plates, a smaller and narrower dorsal plate and a wider 

 and much longer ventral plate. The upper plate is always 

 extremely thin and transparent, usually as long as wide, with the 

 apical side either subtruncate, or rounded, or feebly triangularly 

 produced. 



The ventral plate is usually much longer than wide, with the 

 sides parallel at the basal part, thence convergent either obliquely 

 or arcuatedly and terminating in an acute point. The rim of 

 this plate is slightly thickened, hard and horny, highly polished 

 and of a rich umber brown ; the edge itself is extremely sharp 

 like that of a knife and finely (in one species coarsely) serrate. 

 The middle of the plate from the base to some distance beyond 

 the parallel portion is very thin, quite transparent and concave 

 at the dorsal surface. The dorsal plate closly fits into this con 

 cavity and thus protects the inner parts of the ovipositor, which 

 can be plainly seen through the transparent outer plates. 



The whole apparatus just characterized evidently forms an in 

 strument admirably adapted to sawing into the tissues of plants, 

 and I have not the slightest doubt that in all species of this sub- 

 genus the eggs are laid within the stems or roots of plants. The 

 ovipositor is exserted at an angle with the tip of the abdomen so 

 that the beetle can operate it exactly like a saw moving up- and 

 downward. When the ventral plate has sufficiently deeply pene 

 trated into the plant, the apex of the dorsal plate is lifted up, 

 which can be readily done on account of the higher rim of the- 

 ventral plate. The ovipositor proper, guided by the inner 



