112 



CALIFORNIA STATE COMMISSION OF HORTICULTURE. 



bothering about. They are quiet and insidious in their efforts, but 

 never let go. Some of them get on the inside of their host, in which 

 case they eat him out of house and home before they quit; in other 

 cases they take an attachment on his outside and cling closer than a 

 brother so long as he has a drop of blood in his body. But, however 

 they do it, the result is the same to us; they get away with our foes, so 

 we declare them our friends. But, bearing out Swift's doggerel, there 

 are other parasites on these — secondaries, or hyper- 

 parasites, we call them — and some parasites on 

 these again — tertiaries. So that, in importing bene- 

 ficial insects, we are always very careful to see 

 that there are no secondaries to escape and prey 

 upon them before they are turned loose. Usually, 

 when the egg is laid upon the body of the victim 

 insect, as soon as it is hatched the young larva pro- 

 ceeds to work its way to the inner portions of its 

 host, where it lives 

 secure and waxes fat 

 on his substance. By 

 a strange instinct, 

 however, it carefully 

 avoids the vital por- 

 tions, and so the host 

 insect lives in misery 

 until its parasite has 

 acquired its growth, 

 when it dies. 



While some of the 

 members of this fam- 

 ily are of small size, 

 many of them are 

 large, for parasitic in- 

 sects. The Caliephi- 

 lates messer Grav., of 

 which we give an ex- 

 cellent colored illus- 

 tration elsewhere, is a member of this family. This is a new species 

 in the United States, introduced for work on the codling-moth, of which 

 it has been found a very effective parasite. 



The females of some species of this family are remarkable-looking 

 insects, having an exaggerated ovipositor, which appears like a long 

 tail. This, when folded, looks like one piece, but is really composed 

 of three pieces: the ovipositor proper, and two guards, which form a 

 sheath. The ovipositor itself is composed of three parallel pieces, one 





FIG. 108. Thalessa luna- 

 tor, ichneumon para- 

 site of pigeon tremex 

 (Tremex columba). 



FIG. 109. Thalessa lunator drilling a 

 hole in a tree-trunk in order to de- 

 posit eggs in the burrow of tlie 

 pigeon tremex (Tremex columba). 



