672. 

 CHELONUS WESMAELII. 



Order Hymenoptera. Fam. Ichneumonidae. 



Type of the Genus, Ichneumon oculator Fab. 

 CuELONUs Jur., Panz., Nees, Wesm., Curt. — Sigalphus Lat. 



Antenna inserted near the top of the face, approximating, scarcely 

 so long as the body and 28-jointed in the male ; not longer than 

 the thorax and 24-jointed in the female, rather stout and taper- 

 ing very much at the apex, basal joint long and stout, 2nd sub- 

 globose. 3rd nearly as long as the 1st, the remainder decreasing 

 and becoming turbinate towards the apex (1, a few joints). 

 Labrum inserted under the clypeus, sublunate, the anterior mar- 

 gin straight and pilose, with a large membranous lobe beneath, 

 projecting beyond the labrum (2). 

 Mandibles rather small, trigonate, hairy and bifid (3). 

 ilfff,r27/<e terminated by an obovate coriaceous lobe, and a smaller 

 internal membranous one, both ciliated. Palpi long, slender, 

 pubescent, pilose and 6'-jointed, basal joint the shortest, clavate, 

 2nd longer and stouter, 3rd the stoutest, long and clavate, 4th 

 a little the longest, slender and nearly linear, 5 th and 6th 

 shorter and slender (4). 



Mentum elongated, ovate at the base. Lip moderately long, 

 hollow. Palpi not short, pubescent, pilose and 4-jointed, basal 

 joint elongate-clavate, 2nd as long and stouter, 3rd shoit, stout, 

 obovate, 4th as long as the 1st, slender, apex conical (5). 

 Head transverse, base concave, face suborbicvlar : eyes rather small, 

 lateral, ovate and pubescent : ocelli 'i, forming a compact triangle on 

 the crown. Thorax sabglobose or oblong : scutel triangular : me- 

 tathorax rugose, and toothed at the angles. Abdomen elongate- 

 ovate, clavate (A), the basal joints united and forming a rough shield, 

 the sides and apex inclosing a deep cavity beneath like a wooden shoe : 

 oviduct short, arising from a trigonate valve and not projecting be- 

 yond the apex (0). Wings ample, superior loith 1 marginal, 3 sub- 

 marginal and 1 discoidal cell. Legs moderate : thighs and tibise 

 short, the latter more or less clavate and spurred : tarsi slender and 

 5 -jointed: claws awt/ pul villi distinct. 



Wesmaelii Curt. Guide, Gen. 556. 



This group of insects, rendered remarkable by the absence 

 of abdominal segments, is thus characterized by Nees ab Esen- 

 beck in h.\ii Hymen. Ichn. qffvn. v. I. "Labial palpi 4-jointed: 

 mandibles bifid : abdomen covered with a cuirass, the 3 basal 

 segments united." Wesmael in his Man. des Bracon. de Belg. 

 has divided this group into other genera, which I have adopted 

 in my "Guide," and shall here give his definitions. Besides the 

 following 13 indigenous species there are 10 others recorded. 

 546^. Rhitigaster Wesm. AbdomeJi with the aiir ass composed 

 of 3 segments: radial cell elongate: 3 cubital cells, 2nd elon- 

 gate-quadrate. 

 1. Irrorator Fab.—De Geer, \. p. 577. tab. 36./. 12. 13. 



