590 Mr. C. L. Withycombe's Notes on 



other hand, larvae of C. septemjmndata also supplied with 

 excess of food, have been observed to pupate on as few as 

 71 and 91 aphids respectively. A fair average in the case 

 of Chrysopa is 100. With Coniopterygids the amount of 

 food taken is not so easy to determine, and the larva when 

 feeding often does not suck its prey at all completely. 

 Oak leaves covered with ova, and newly-hatched Phylloxera 

 punctata Licht., were given to Coniventzia and Semidalis 

 larvae. The number of both ova and young destroyed 

 during the life of the larva, about three weeks, must have 

 been between 150 and 300. 



Checks and Parasites. 



A gram-positive Micrococcus, of about 1/i diameter, 

 causes a disease in larvae similar to flacherie. The bacterium 

 obtains entry to the body via the anus, which, as has been 

 previously noted, often exudes a drop of viscous adhaesive 

 fluid. The larva turns black and dies. This disease is 

 very infectious and boxes have to be sterilised before use 

 for another larva. The disease is rarely met with in 

 nature. 



Larvae of Chrysopa prasina and ventralis, and some 

 larvae wintering in the cocoon, die, and later give rise to 

 a growth of Penicilliimi sp. I have not yet proved that 

 the fungus is the cause of death or whether it is only 

 saprophytic. 



Imagines of H. stigma, especially late in the season, may 

 be infested with a cephaline gregarine parasite, in the 

 mid- and hind-gut. Uninfected imagines placed in a box 

 in which infected specimens have lived become also infected, 

 and I have good reason to believe that this is by eating the 

 infected excreta, since imagines have often been observed 

 to eat each other's excrement. Infection in wild caught 

 insects in autumn is often as high as 50 per cent, in some 

 districts. Little harm appears to be done by the parasite, 

 infected females continue to lay fertile eggs. 



Hymenopterous parasites attack all stages except the 

 imago. Sisyra and Conwentzia are attacked while as 

 larvae awaiting pupation within the cocoon. Thus Lygo- 

 cerus sp, bites a hole in the cocoon of C. psocifortnis, with 

 its mandibles, then often bites or bruises the Coniventzia 

 larva on the thorax, probably to prevent pupation, and 

 finally lays an egg beside the larva. The parasitic larva 



