20 MONOGRAPHIA CHALCIDUM. 



Sp. 16. Isos. pusillum. Mas. Nigrum, prothorace ant'ice 

 maculis duahus albidis, alts subfuscis. 



Caput obscurum : oculi ocellique rufi : thorax punctatus, maculis 

 antice cluabus lateralibus albidis : petiolus obscurus, punctatus : 

 abdomen nitidum, glabrum ; tibiae nigro-fuscas : tarsi fusci : genua 

 flava : alse subfuscae. (Alarum longitudo, I lin.) 



Like the preceding, but shorter, and the antennae are 

 thicker. 



End of May ; amongst grass in fields ; Southampton. 



Sp. 17. Isos. breviventre. Mas et fem. Nigrum, prothorace 

 antice maculis duahus albidis, alis hyalinis. 



Caput obscvirum : oculi ocellique rufi : thorax punctatus, maculis 

 antice duabus lateralibus albidis : petiolus obscurus, punctatus : 

 abdomen nitidum, glabrum, breve : genua tarsique flavi : alae 

 hyalinse, nervis pallide fuscis. (Alarum longitudo, f lin.) 

 It is shorter than Isos. tenuicorne, or minor: from the former 

 it differs also by its thick antennae, their greater length dis- 

 tinguishes it from Isos. pusillum. 



End of May ; amongst grass in fields ; Southampton. 



Sp. 18. Isos. angustatum. Fem. Nigrum, prothorace antice 

 maculis duabus albidis, alis pallide, fiavojuscis. 



Caput obscurum : oculi ocellique rufi : thorax punctatus, maculis 

 antice duabus lateralibus albidis : petiolus obscurus, punctatus : 

 abdomen nitidum, glabrum : femora et tibiae apice flavse : tarsi 

 flavi, articulis 4 et 5, nigro-fuscis : alae pallide flavofuscse, nervis 

 concoloribus. (Alarum longitudo, 1:^ — If lin.) 



It is more linear than any of the preceding species, and the 

 colour of the first, second, and third tarsal joints is brighter, 

 the fourth and fifth joints are dark fuscous : the wings are 

 very slightly tinged with yellow, the nervures are pale : it much 

 resembles the female of the preceding species, but is larger, and 

 has thicker antennas. 



June, July ; amongst grass in fields ; Southgate. Sep- 

 tember ; Isle of Wight. 



Sp. 19. Isos. dissimile. Mas. Nigrum, prothorace antice 

 maculis duabus albidis, tibiis anticis fuscis, alis hyalinis. 



Caput obscurum : oculi ocellique rufi : thorax punctatus, maculis 

 antice duabus lateralibus albidis : petiolus obscurus, punctatus : 



