30 OYSTER-SHELL BARK-LOUSE. 



this number in our species is that we have not happened to see 

 them all separated. The length of this proboscis is also difficult 

 to be ascertained, on account of its fragility, and the consequent 

 doubt, in any case, whether we have extracted the whole of it 

 from the bark. In my experience it has usually broken off, either 

 close to the body, or of a length somewhat less than that of the 

 body, though I have seen it considerably longer. M. Signoret 

 says that in some species he has seen it twice the length of the in- 

 sect's body, and in rare instances even three times as long. 1 

 once removed a young female of the pine leaf species {Afytilaspis 

 2)inifoli(E, Fitch) just as it was beginning to form the terminal 

 shield, and when it was scarcely one-thirtieth of an inch long, in 

 which the proboscis was two lines, or one-sixth of an inch in 

 length, by actual measurement, and therefore fully live times the 

 length of the insect's body. In this instance I noticed that the 

 proboscis was filiform, or of equal thickness for the greater part 

 of its length, and that it thence tapered to a very fine point, from 

 which I concluded that I had succeeded in extracting the whole of 

 the instrument from the leaf. 



It is difficult to conceive how so delicate and fragile an organ 

 can be inserted into the leaf, and much more into the tough tissue 

 of the bark. I once succeeded in tracing the proboscis of the 

 Pine-louse, for about half its length, running horizontally, just un- 

 der the semi-transparent cuticle, and it is not improbable that this 

 is the situation in which the instrument is usually introduced. 

 Notwithstanding the sluggish and apparently almost lifeless con- 

 dition of the female Coccus^ the proboscis seems to be endowed 

 with a special vitality. I have often seen it move with a waving 

 or serpentine motion, and M. Signoret thinks it is capable of a 

 considerable degree of extension and retraction, and it was some 

 action of the attached proboscis, no doubt, which produced the 

 jerking motion of the insect's body noticed by Dr. Shimer. 



Upon the interesting topics of the diflerence of the sexes in 

 this tribe of insects, and the nature and growth of the scale by 

 which they are protected, we hav3 made a somewhat systematic 

 series of observations during the past season, but we have prefer- 

 red to avail ourselves, for this purpose, of the species which dwells 

 on the pine-leaf, for the reason that the existence and characters 

 of the male of this species are known, and that the several parts 



