394 THE GYPSY MOTH. 



ally distributed throughout the infested region, and the 

 good they do in destroying the caterpillars of this insect is 

 of no little importance. The larger of the two species, 

 P. cynicus, occurs in smaller numbers than P. serirventris, 

 and, although it will destroy more caterpillars during its 

 feeding season, yet from the moderate numbers in which 

 it occurs it is not so valuable an ally as P. serieventris. 

 Whether these insects are devoured by birds to any great 

 extent I am unable to state. The odoriferous glands with 

 which they are provided would seem to be a means of pro- 

 tection against their natural enemies. A pair of crows, 

 confined at the insectary, devoured all specimens offered 

 them of the three species of these bugs, and Mr. Forbush 

 informs me that in nature these insects may possibly be 

 destroyed to some extent by crows, since these birds are 

 known to include the Heteroptera in their bill of fare. 



Method of rearing Predaceous Bugs. The problem of 

 breeding any Heteropterous insect presents at the outset 

 many difficulties, and but little assistance is given by the 

 literature on this sub-order of insects. Concerning this sub- 

 ject, Douglas and Scott, in their work on " British Hemip- 

 tera," Vol. I, page 5, 1865, wrote: "It is probable, in 

 consequence of the fact that the Hemiptera-Heteroptera are 

 in all stages of their existence active and suctorial, and the 

 consequent difficulty of supplying them, in confinement, with 

 fresh, appropriate food, that but few observations upon their 

 natural history have been recorded. . . . But, whether 

 each species casts its skin the same number of times ; how 

 long the individuals of each species remain as larva, pupa 

 or imago ; what species have more than one brood in a 

 year, and what constitutes the food of each species, are 

 matters that, in the great majority of instances, remain to 

 be determined. There is, therefore, a wide field for re- 

 search in the natural history of this sub-order of insects." 



While considerable has been done toward gaining a 

 knowledge of the life histories of many of our plant-feeding 

 Heteroptera, in the thirty years which have elapsed since 

 the above was written, as yet we know but little of the life 

 history of those members of the family which are predaceous 



