86 



The observations and experience of this spring have brought into 

 question the real value, as aids to the fruit grower, of the four pre- 

 daceous insects mentioned and others of the same class which have 

 general feeding habits. The evidence points verj- strongly to the 

 conclusion that such insects do more harm by destroying beneficial 

 species like the ladybirds feeding on scale and plant-lice than they will 

 ever do good by eating larvae or other soft-bodied plant-feeding insects. 

 In other words, the injurious insects which they may feed upon to a 

 greater or less extent are almost without exception species which are 

 very easily controlled by other means, viz, by insecticides or methods 

 of cropping. On the other hand, the beneficial insects which they 

 destroy, as notably the larvae of ladybirds, which feed on plant-lice 

 and scale insects, include a group of insects of special importance and 

 value to the horticulturist, for the reason that they feed on insects 

 which are not easily controlled by other means, and which, if kept in 

 control by natural enemies, may never require the expensive and, to 

 the plants, dangerous treatment necessary to effect their artificial 

 destruction. As a general proposition, therefore, I am inclined to 

 rank all general-feeding predaceous insects as injurious and distinctly 

 prejudicial to the interests of the horticulturist and farmer. The 

 introduction, therefore, of any such insect, as, for example, the 

 European Mantis reUgiosa, or eiforts at their wider dissemination, are 

 mistakes, which, in my opinion, will come to be regretted very keenly 

 in the future. Instead of protecting these insects, I believe it will be 

 much more to the general advantage to destroy all e^g masses of 

 mantids and the wheel bug; and to view the lace-winged flies with 

 suspicion, if not to class them as absolute foes. 



ADDENDUM. 



A very important hymenopterous parasite must be added to the list 

 of natural enemies of the Asiatic ladybird. To our very great disap- 

 pointment and astonishment, early in September it was found that the 

 pupae of the last brood were much parasitized, causing a loss of more 

 than 10 per cent of this brood. As many as could be of these para- 

 sitized pupae have been collected, and from them has been reared a 

 little Chalcidid fly, Syiitomosjjhynon esurnx Riley, from five to seven 

 parasites coming from each pupa. This insect belongs with a group 

 of secondary parasites, but no trace of the primary parasite could be 

 found in any of the pupae examined, although later breeding may 

 develop the primary parasite during the winter or next spring. The 

 larvae were found free in the abdominal cavity of the Chilocorus pupa, 

 and ultimately all of the substance of the pupa disappears. In one or 

 two cases where parasitism had only just begun to make itself evident, 

 half -grown larva? were found. These were filled with the yellow fluid 

 contents of the Chrysomelid, and were orange yellow in color. The 



