258 THE ENTOMOLOGIST. 



to Mr. E. South for confirming the names of hosts, and to Mr. 

 B. S. Harwood, of Colchester, who has sent me for examination 

 a considerable number of specimens, most of which have come 

 to him from the collection of the late E. A. Fitch. Although 

 the main part of the Fitch collection is now in the Essex 

 Museum at Stratford, it would seem that the insects which are 

 at present in the possession of Mr. Harwood were put on one 

 side in store-boxes, some as duplicates and others as being un- 

 named, or to await naming, and have so remained for the past 

 twenty years or more. 



In the following notes, unless otherwise stated, the records 

 are my own, and the insects mentioned have been captured or 

 bred in tbe New Forest. 



Macrocentrus, Curtis.* 

 Gregarious or solitary parasites of larvae of Lepidoptera. 

 Eatzeburg records one species as having been bred from the 

 coleof)teron Avohhnn j^ertinax, but this has never been confirmed. 

 The general colour of these insects is black with rufous or 

 testaceous markings. In the few cases where I have noticed the 

 larvae, they have been elongate and whitish without any very 

 noticeable markings. It is possible that in all the species the 

 larvfe may be partially external parasites, for with M. ahdomi- 

 nalis and M. equalis I have found that, although internal feeders 

 when small, the larvae feed for three or four days as external 

 parasites after emerging from their host, during which time 

 they rapidly increase in size. 



Antenna} with forty-five or more joints. 

 2. Third abdominal segment (like the two pre- 

 ceding) entirely striolate . 1. abdominalis (Fab.). 

 Third abdominal segment smooth, or strio- 

 late at base only. 

 Body entirely black. 



Stout species, wings clouded . 2. marginator (Nees). 

 Slender species, wings hyaline . 8. nitidus (Wesm.). 

 Thorax rufous .... 4. tJioracicus (Nees). 

 Antennse with forty or less joints. 

 Second abscissa of radius as long as the first 

 intercubital nervure. 

 (11) 10. Body entirely black, terebra longer than 



body 5. infirmus (Nees). 



(10) 11. Thorax partly rufo-testaceous, terebra not 



longer than the abdomen . 6. equalis (sp. nov.). 



(9) 12. Second abscissa of radius much shorter than 



first intercubital nervure . 7. collaris (Spin.). 



M. abdominalis, Fab.f — Without doubt the commonest species 

 in the genus, having now been recorded as bred from nearly 



* Ent. Mag., vol. i., p. 187. f Ent. Systematica, 2, 183. 



