on the British Species Cissida. 209 



blance to the C. nit'/dus, but decidedly smaller, has the thorax 

 contracted in front, and with the anterior angles obtuse — not pro- 

 duced as in C. n'ltidus. A more marked distinction, however, is 

 seen in the structure of the antennae, which, instead of being 

 ten-jointed, as in Cis^ are eight-jointed, viz., two stout joints at 

 the base, followed by an elongate slender joint, then a short ob- 

 conic joint, and between this and the three-jointed club a small 

 transverse joint ; the thorax is finely, but not densely punctured; 

 the elytra are rather finely punctured, and rugulose. 

 Common in Boleli, near London and elsewhere. 



XV. Notes on the Economy of the Ichneumons constituting 

 the Genus Pczomachus of Gravenhorst, and Obser- 

 vations on Pezomachus fasciatus, by Frederick 

 Smith, Esq.; with a Description of a New Species 

 of Hemiteles, by Thomas Desvignes, Esq. 



[Read July 4lli, 1859.J 



The observations of Hymenopterists on the species of the genus 

 Pezomachus have in some instances tended to prove that these 

 Ichneumons are the parasites of parasites. Ratzeburg states that 

 he obtained Pezomachus agilis, P. inslahilis and P. terebrator from 

 a species of Microgasler ; Pezomachus cursitans has been reared 

 from the cocoons of Cryptiis incubator. Ratzeburg obtained 

 Pezomachus from the cocoons of Loplnjrus Pini, and also from 

 those of Cimbex variabilis; in the two latter cases there does not 

 appear to be any proof that the Pezomachi did not prey upon the 

 larvae of the saw-flies themselves ; he also obtained P. inslabilis 

 from the nest of a spider. Dahlbom has reared a species of Peso- 

 machus from a small moth belonging to the family Tineina — Hi/po- 

 nomeuta Evonijmellus ; Foerster has recorded the above facts in his 

 Monograph on the genus Pezomachus. 



Mr. Haliday has also reared a species of Pezomachus from the 

 cocoons of Microgasler intricatus, as is recorded in the second 

 volume of the " Entomological Magazine." 



Mr. Westwood, in his great work on the " Modern Classifica- 

 tion of Insects," informs us, that other species of Ichneumons de- 

 posit their eggs in the silken cocoons of various species of spiders, 



VOL. V. N.S. PART V. — MARCH, 1860. P 



