THEREVA — 0CM1A. 163 



on the cross-veins and on the bifurcations) ; very irregular brownish-grey clouds inside 

 the cells, more or less filling out their surface ; venation normal, the upper branch of 

 the third vein somewhat S-shaped, the fourth posterior cell broadly open, although 

 coarctate. A single female. 



N.B. — The chsetotaxy, so far as I can judge from the scars (many bristles being 

 rubbed off), is the normal one of Thereva, as described in my essay on " Cheetotaxy." 

 The same may be said of the bristles on the legs. 



The following five species of Therevidse have been described from Mexico (there are 

 none from other parts of Central America) : — 



Thereva crassieornis, Bellardi, Saggio &c. ii. p. 88, t. 2. f. 16. — Mexico. 



argentata, Bellardi, 1. c. ii. p. 89. — Mexico, Cordova. 



Psilocephala univittata, Bellardi, 1. c. ii. p. 90. — Mexico, Puebla. 



sumichrasti, Bellardi, 1. c. ii. p. 91. — Mexico, Tuxpango near Orizaba. 



(Dialineura) nigra, Bellardi, 1. c. ii. p. 92. — Mexico (a different species 



from the following). 

 (Thereva) nigra, Say, Complete Writings, ii. p. 57; van der Wulp, 



Tijdschr. voor Ent. xxv. p. 118. — Pennsylvania, Mexico. 



In this connection the " Scenopinid" Pseudatrichia longurio, Loew, Centur. vii. no. 76, 

 from Mexico, may also be mentioned. 



Fam. CYETIDJE. 



The following Cyrtidge from Mexico have been hitherto described (there are none 

 from other parts of Central America) : — 



Ocncea micans, Erichs. Entomogr. i. p. 155. — Mexico. 



Apelleia vittata, Bellardi, Saggio &c. Append, p. 19, f. 12. — Mexico, Playa 



Vicente. (N.B. — Apelleia is an Ocncea with glabrous eyes; comp. 



O. Sack. Bed. ent. Zeit. 1883, p. 25.) 

 Philopota truquii, Bellardi, 1. c. i. p. 77, t. 2. ff. 20, 20 bis. — Mexico, Cuazi- 



malpa. 



To these I now add the following : — 



OCN.EA. 



Ocneea, Erichson, Entomographien, i. (1840) . 



l. Ocnaea grossa, sp. n., <$ . (Tab. III. fig. 7.) 



Eyes glabrous. Antennae velvety-black ; the joints of the scapus of nearly equal length ; the third joint at least 

 eight times the length of the preceding two together, a little stouter at the base, the tip obtuse. Thorax 

 black, clothed with a dense fur of brown hair, with fulvous reflections (the posterior part of the mesothorax 



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