Sauborn.] 326 [November 2", 



Mr. F. G. Sanborn exhibited a specimen of Libellula hic- 

 tuosa Burm. 9 , presenting a singular malformation, or arrest 

 of development, in the anterior wing. 



The wing is comparatively well proportioned from the base to 

 the nodus, though bearing marks of differentiation from the normal ar- 

 rangement of nervures. The pterostigma, however, is perceptibly 

 shorter and broader than that of the opposite wing, and is situated 

 about one eighth of an inch only from the nodus, only one cubital vein 

 occurring between them, instead o^ four- 

 teen as in the opposite wing. The mar- 

 gin is thickened, and the apex of the 

 wing truncated and compressed, as if 

 a crushing force had been applied in 

 the direction of its length and had spent its strength on the 

 external half of the wing. 



He also exhibited several speci«iens illustrating Insect Econoni}-, 

 viz. :— 



1. The winter larva-cases of Limenitis Missippus shown by Mr. L. 

 Trouvelot at a previous meeting. These cases, composed of the leaf 

 of the willow on which the larva feeds, are neatly joined by their 

 longest opposite margins, so as to form a cylindrical tube closed at 

 one end and lined with the sericeous substance spun by the inhabi- 

 tant. 



2. The larva-skin of an (Edipoda impaled on a needle or leaf of 

 pine ; these specimens are frequently found, as also the same cast skins 

 impaled on leaves of grass. The head of the insect is always di- 

 rected toward the base of the leaves so far as I have observed, giving 

 rise to the very natural conclusion that when about to moult the 

 larva pushes its head against the point of the leaf, and crawling on- 

 ward makes use of the purchase thus obtained in divesting itself of 

 its skin. The specimens thus impaled — so far as observed — were 

 always quite young individuals of Caloptenus or some species of 



*(Edipoda . 



3. Skins of Aphides on a poplar twig in great numbei-s, and two other 

 species on leaves of apple. These skins had been emptied of their 

 contents by a Hymenopterous parasite, ApJddius, which had escaped 

 after its transformation hj- gnawing a nearly comj^lete circle through 

 the dry skin, thus partially detaching a neatly rounded lid or cover, 

 which hung by a small portion of its circumference as by a hinge. 



4. Two acorn-cups which had been made use of by spiders, one as a 

 retreat, the opening of the cup being flatly roofed over with web 

 leaving only a small aperture for ingress and egress. The spider 



