17. 

 CRCESUS SEPTENTRIONALIS. 



Order Hymenoptera. Fam. Tenthredinidae Lat. 



Type of the Genus, Tenthredo septentrionalis Linn. 

 Crcesus Leach, Curt. — Nematus Jur., Lat. — Tenthredo Linn. Fab. 



Antenna inserted between the eyes in front of the head, alike in both 

 sexes, rather long setaceous pubescent and 9-jointed, basal joint 

 short, 2nd cup-shaped, the remainder long but decreasing in length 

 to the apex (1). 



Labrum exserted, transverse, pilose and ciliated, sides rounded, an- 

 terior margin slightly convex (2). 



Mandibles small, robust, elongate-trigonate, acute, with a tooth on the 

 inside below the apex (3) . 



Maxillce elongated, corneous at the base (4 a), dilated above, the in- 

 ternal margin pubescent with a tooth at the apex (c), terminal lobe 

 membranous and subovate. Palpi long, pubescent and 6-jointed, basal 

 joint obovate, 2nd elongated, 3rd longer and stouter, 4th and 5th the 

 longestj 6th shorter, slender and filiform (b). 



Mentum quadrate, dilated and emarginate before (5 a). Palpi pube- 

 scent, composed of 4 joints of nearly equal length, basal joint clavate, 

 3rd the stoutest and bent, 4th elliptic-conic (6). Lip membranous, 

 trilobed, external ones large, subhemispherical, striated and pubescent 

 externally, central lobe narrow and spatulate (c). 

 Males smaller than the females. Clypeus transverse, emarginate. Head 

 transverse, face orbicular : eyes oval : ocelli 3 on the crown. Thorax sub- 

 globose. Abdomen sessile, short ovate-conic : oviduct concealed. Supe- 

 rior wings with 1 marginal and 4 submarginal cells, the 1st small, almost 

 round, 2nd large and receiving 2 recurrent nervures, 3rd small quadrate. 

 Legs, hinder the largest in both sexes : tibiae with spurs at the apex, longest 

 in the hinder pair which are much dilated: tarsi b-jointed, basal joint very 

 much dilated in the hinder pair and subelliptic, the other joints very short : 

 claws bifid: pulvilli distinct. (8, afore leg.) 

 Larvae attenuated behind, with 6 pectoral, 1 2 abdominal and 2 anal feet. 

 Pupa inclosed in a cocoon in the earth. 



Septentrionalis Linn. — Curt. Guide, Gen. 471. 1. 



Male black, base of antennae, excepting the 2 first joints, brown : ab- 

 domen rufous, except the 2 basal segments : superior wings yellowish 

 beyond the middle where there is a faint brown cloud ; stigma brown : 

 legs rufous-ochre, hinder coxae black, the apex as well as the tro- 

 chanters whitish : tips of hinder thighs black, posterior tibiae and tarsi 

 pitchy, the former white at the base. Female, antennae and apex of 

 abdomen black : thighs black, apex of anterior ochreous ; tibiae and 

 tarsi ochreous, base of the former whitish, hinder tibiae and tarsi black, 

 base of the former white, the spurs ochreous. 



In the Author's and other Cabinets. 



