BY R. J. TILLYARD. 815 



wool which I had supplied for that purpose. She also explored 

 the bark, but found it for the most part unsuitable, laying only 

 one egg there, as against eleven laid on the cotton- wool. The 

 two eggs shown in Text-fig. 1 were laid close together as drawn, 

 but all the rest were quite separate. This female may, of course, 

 have laid other eggs which I failed to find. I should say that a 

 single female must contain at least fifty eggs;* but it is possible 

 that they would not usually all be laid after a single pairing. 



The males were kept alive for periods varying from ten days 

 to three weeks. The females live longer, and one was kept alive 

 for over a month, by which time her wings were considerably 

 torn. The only nourishment given, during all this time, was 

 sugar and water, which I find sufficient for most Planipennia 

 and Mecoptera. A very slight degree of moisture is required in 

 the jar. Either excess of moisture, or exposure to a hot drying 

 wind, is equally injurious to these insects The same may be 

 said of all Planipennia, although the MyrmeleontidcH and Ascala- 

 phidce can stand greater heat and desiccation than any of the 

 others. 



The Economic Value of the Psychopsidae. 



There is no Order of Insects, with the exception of the 

 Hymenoptera, whose members are so generally beneficial to man- 

 kind as the Planipennia. It seems, therefore, of considerable 

 importance that we should now attempt to estimate the value of 

 the Psychopsidce in this respect. 



From the account of the life-history here given, it will be seen 

 at once that these insects are entirely beneficial to man through- 

 out their whole life. The preference shown by the larva for 

 feeding upon such obnoxious insects as the larv?e of Codlin 

 Moth, and other of the smaller Lepidoptera, at once establishes 

 it as potentially a very useful factor in the checking of insect- 

 pests. Hence, if colonies of Psychopsis could be established in 

 our apple-, pear-, and quince-orchards, there is no doubt that 

 they would help very materially in checking the Codlin Moth 

 and other Lepidopterous pests that still do so much damage 

 therein. 



* Mr. Gallard's original female laid over fifty eggs. See p. 787. 



