116 MONOGRAPHIA 



antennae slender and filiform, the second joint rather the 

 longest ; prothorax quadrangular, lateral margin fuscous ; 

 metathorax as wide as the head, posterior margin angular, 

 lateral margin fuscous and produced ; abdomen oblong, the 

 lateral margin of the first seven segments, with a pitchy 

 black fascia, shading internally into chestnut, the eighth 

 segment with a transverse chestnut band ; legs pale yellow, 

 femora with the superior margin, and tibiae with a spot at 

 the apex, fuscous. Length f . 



I have seen but one specimen of this species, which I 

 took from a skin of the Nutcracker (Nucifraga caryocatac- 

 tes), and suppose it to be the N. Olivaceus of Dr. Bur- 

 meister. 



6. NIRMUS GRACILIS. (Louse of the House Martin.) 



Plate XI. Fig. 7. 



Pale yellow- white, shining and smooth ; head rotun- 

 date, with a conical spot on each side ; abdomen with deep 

 chestnut fasci on the lateral margin. 



Nirmus gracilis. Burmeister Handbuch ii. pt. ii. p. 429. sp. 15. 



Head and thorax bright chestnut yellow, the former ro- 

 tundate-trigonate, slightly depressed in the centre; clypeus 

 sub-emarginate, lateral margin entire, with an angular liver 

 coloured spot before the antennae, base truncate ; antennae 

 short and slender; prothorax quadrangular; metathorax 

 transverse, posterior margin angular and produced, lateral 

 margin of both deep chestnut ; abdomen obovate, lateral 

 margin serrulate, the first seven segments with a deep 

 chestnut subangular patch on each side, darker beneath ; 

 legs short and thick ; tibiae with a fuscous line on the supe- 

 rior margin. Length^. 



Infests the House Martin (Hirundo urbica). 



