108 ILLINOIS BIOLOGICAL MONOGRAPHS [426 



brown; tenth abdominal sternum with small brown round spot on each side; length, 

 16 mm.; width of head, 1.6 mm.; larvae solitary, leaf-edge rollers on Comus; M. 



Pamphilius ocreatus Say. 



Family Cephidae 



Body (Fig. 2) cylindrical, sometimes slightly depressed, enlarged at 

 thorax, slightly and uniformly tapering caudad, slender or moderately 

 stout; segmentation usually distinct; annulation sometimes indistinct; 

 cuticle smooth or verrucose, microscopically and very sparsely setiferous; 

 color generallly pale or creamy white, never with distinct bright marks; 

 head circular in contour, semiglobose, moderately large, narrower than 

 thorax, caudal portion concealed by prothorax, pale brown or concojorous 

 with body, sparsely setiferous; mouth-parts directed ventrad, normal 

 in form, brownish; antennae with four or five segments, conical; ocellarae 

 small, with ocularia less than one-fifth the diameter of antennaria and 

 located latero-caudad of it; epicranial suture and vertical furrows present; 

 mesothorax distinctly, and metathorax with dorsal and lateral aspects 

 somewhat swollen; thoracic legs vestigial, fleshy, mamma-like, tarsal 

 claws wanting; third abdominal segment with two or three annulets, 

 sometimes indistinct; venter with three annulets; larvapods wanting, 

 sometimes with slight swellings in normal position of larvapods; lateral 

 lobes prominent, extending the entire length of the segment; tergum of 

 ultimate segment with mesal longitudinal broad depression and distinct 

 suranal process; sternum of ultimate segment with a pair of inconspicuous 

 vestigial, papilliform subanal appendages ventrad of the cephalic end of 

 the anal slit; internal feeders, boring into the stem of monocotyledonous 

 and herbaceous plants and bushes; pupation in tunnels in the host-plants. 



The Cephidae contains about fourteen genera and is moderately rich 

 in number of species, some of them of intercontinental distribution. 

 Nine genera are represented in North America. Practically all systematists 

 have considered this group as a distinct aggregate worthy of family rank. 

 Rohwer (1911), however, has expressed the opinion that future studies 

 may possibly make it advisable to unite this group with the Xyelidae 

 and to treat each of them as subfamilies. There have so far been no facts 

 or reasons brought to light which call for such a step. On the other hand, 

 MacGillivray's study has emphasized the fact that "so far as the wings 

 are concerned, they (Cephidae) are the most distinct of any group of the 

 Tenthredinoidea, and are only indirectly related to any of the other 

 families." They are generalized in the manner of the origin of media 

 but are specialized in other features of the wings. On the basis of larval 

 characters this family is related to the Pamphiliidae and is quite unrelated 

 to the Xyelidae. 



The systematic position of the osculant genus Syntexis is unsettled. 

 In the original description Rohwer (1915) stated that this genus has 



