THE PRESERVERS OF THE CABBAGE. 325 



long ovipositor. The present species is nearly as variable in 

 size as the Pimpla which has just been described. Its colour 

 is black, diversified by bright yellow spots along the sides of 

 the thorax and body, as seen in the illustration. Like some 

 other Ichneumons with very long ovipositors, it is parasitic on 

 larvae which burrow into solid wood. 



On Plate X. Fig. 6, is seen a magnified figure of a curious 

 insect, called Chelonus oculator. In this genus there are two 

 submarginal cells, the first of which is not complete. The 

 eyes are hairy. This species is not a common insect, and seems 

 to be a local and recurrent one. Mr. F. Smith tells me that in 

 one day he took more than fifty specimens, by sweeping the grass 

 on the top of the cliffs at Lowestoft, and that he has hardlv ever 

 seen as many since as he took on that one occasion. The 

 colour of the insect is black, some specimens, particularly the 

 males, having a yellow band across the abdomen. It is, how- 

 ever, very variable both in size and colour. The economy of 

 this insect is very ciu'ious, and is not thoroughly cleared up. 



On Woodcut XXXI I. Fig. 1, may be seen a much magnified 

 illustration of a very small but singularly useful insect — so 

 useful, indeed, that without its aid we should scarcely be able 

 to raise a single cabbage. This is called Microgaster glome- 

 ratus. In this genus the eyes are hairy, the antennae long and 

 consisting of eighteen joints. The present species is dark- 

 bodied, and its wings are translucent, but, when viewed throuo-h 

 the microscope, are wonderfully beautiful, glittering with every 

 hue of the rainbow as the light plays over them. 



This little insect is parasitic on the common Cabbage-cater- 

 pillar, i.e. the larva of the Gfreat Cabbage White Butterfly, and 

 so rapidly does it multiply that, after watching its progress 

 from the larva to maturity, it seems strange that a single 

 Cabbage White Butterfly should be found in the country. 

 Owing to its numbers, the young entomologist will find this 

 insect an admirable one for experiments. If a hundred Cab- 

 bage-caterpillars be captured, there will be only one or two 

 whicli do not contain the larvae of the Microgaster. Their rela- 

 tive size in proportion to the caterpillar is shown at Plo-. c of 

 the same Woodcut, but neither their numbers nor their position. 



