OF NATURAL HISTORY. 713 



transverse, dilated, deeply indented groove at base of the 

 scutel, having small raised lines within, which are not very ob- 

 vious : wino-s hyaline : nervure of the radial cellule obsolete at 

 base; second cubital cellule destitute of the exterior nervure : 

 stigma triangular, fuscous : tergum oblong-oval, punctured, gla- 

 brous, and polished at tip; basal segment rather rough, the 

 lateral edge a little elevated and dull yellowish ; venter each side, 

 excepting at tip, dull yellowish : oviduct not exserted beyond the 

 tip of the abdomen : feet honey-yellow, tips of the posterior 

 thighs above slightly blackish. 



Length nearly one-tenth of an inch. 



It resembles the cnsiyer very much in its markings, but the 

 oviduct is not exserted. Great numbers are deposited together, 

 and they ultimately spin their cocoons and envelope them with 

 an exquisitely fine silky substance, which has been called '' ani- 

 mal cotton." 



4. M. CONGREOATA.— Black ; thorax destitute of oblique, lined 

 sutures ; abdomen elongate, subfusiform. 



Inhabits Pennsylvania. 



% Body black : mandibles and palpi white : thorax destitute ot 

 oblique, lined sutures; transverse suture at the base of the scutel 

 dilated, profound : wings hyaline; radial cellule with the ner- 

 vure as obvious as the others ; second cubital cellule rounded de- 

 stitute of the exterior [263] nervure ; apical nervures obsolete : 

 stio-ma triangular, fuscous : abdomen oblong, subfusiform, more 

 polished than the thorax; first and second joints densely punc- 

 tured or minutely lineated; the first joint pedunculilorm, ar- 

 cuated, narrower than the second : venter along the middle pale 

 yellowish : feet honey-yellow : posterior tibi^ at tip and posterior 



tarsi dusky. 



Length over one-tenth of an inch. 



Resembles .^dUpes, but the thorax has not the oblique, lineated 

 grooves, and the abdomen is more elongated and ^l^^^/^; '^^ ^^^f; 

 Ihis basal segment, like that of the meUi^es, has a slight tubeicle 



on each side. . t • i i e ^^.\^ «v^p 



lu June, 1822, I obtained eighty-four individuals of thi. spe- 

 cies from the larva of a Sphynx. 

 1835.] 



