May 1, 1869.] 



HAEDWICKE'S SCIENCE-GOSSIP. 



Ill 



THE CUCKOO-SPIT. 



A TALL Begonia, standing against the glass, 

 was lighted up with great beauty by the sun- 

 shine of last September, when a little sparkling 

 drop was every now and then observed to fall across 

 the semi-transparent leaves and stem. On exami- 

 nation it was found to proceed from a congregation 

 of cuckoo-spits formed under one of the upper 

 leaves. Here, then, was this insect in its perfect 

 state, feeding on the sap, just as the larva had 

 done ; only throwing off the superfluous moisture 

 in tiny drops, instead of blowing bubbles. The 

 inference drawn on this subject in a former paper 



Fig. 82. Proboscis of Cuckoo-spit larvre, with second set 

 of instruments, and their muscular appendages. 



is therefore confirmed {vide Science-Gossip, July, 

 1868). De Geer, I have since learned, has made 

 the same observation. It may be interesting to 

 make a few remarks on the proboscis which does 



other so closely as to form an air-tight tube, through 

 which the sap is drawn by the powerful suction 

 pump above. It is accompanied by two serrated 

 lancets, one on either side, which widen the punc- 

 ture made by the tube, prevent its pinching, and 

 admit the pressure of the air. Whether the parts 

 of the tube in a proboscis of this character slide 

 upon each other when in action to increase the 

 power of penetration, has been much discussed, 

 and, on very high authority, it has been contended 

 that they do not ; but it may be submitted that, in 

 this instance, the parts of the tube are furnished 

 with the same muscular appendages as the lancets, 

 which are necessarily motile. In examining nu- 

 merous specimens of the larva, it was observed that 

 a few, perhaps one in ten, differ from the rest, in 

 having a muscular coil on each side of the head. 

 A high magnifying power brought out the true 

 character of this. These favoured few were pro- 

 vided with a double set of cutting instruments, as 

 are some of the higher mammals with a second set 

 of teeth. The points of these additional parts rest 

 just above the terminations of the muscles of the 

 first set each to each, and so are ready to advance 

 and slide into place when required. Why only a 

 few should be so provided, it is not for us to ask. 

 This insect, from the moment of being hatched in 

 spring until it deposits its eggs at the close of the 

 year, depends on its proboscis for a supply of food 

 — a long time for so delicate an instrument to last 

 unimpaired, especially in seasons of drought like the 

 last, which thrive and harden the leaves and stems of 

 plants. Nature, therefore, so to speak, in kind 

 solicitude for the preservation of this little link in 

 the chain of animated beings, has given to a select 

 few a second chance ; a reserve for occasions of diffi- 

 culty and danger, as in the instance of the small 

 eggar moth, adduced by Professor Westwood (in 

 the "Entomologist's Text Book," p. 211), some few 

 of which, by another method, are preserved through 

 inclement seasons, that the species might not be- 

 come extinct. Such is the explanation offered of 

 this remarkable fact, which, as it is only occasional, 

 may have hitherto escaped observation. S. S. 



Fig. 83. Part of the second set on one side, highly 

 magnified (x 200). 



this little creature such good service, and es- 

 pecially on the provision made, in some few cases, 

 for its renewal or repair. The form of the pro- 

 boscis is a frequent one. Two half cylinders, with 

 foliated edges and sharpened points, lit into each 



GEOLOGY. 



Ento.uostbaca in Shale.— In a recent number 

 I see a notice of a new Entomostraca found in the 

 roof of the coal-seam at Cramlington by Mr. Thomas 

 Atthey. In some coal shale I have got from Brad- 

 ford, near Manchester, I find these Entomostraca in 

 great abundance. A small portion of this shale, 

 viewed under a low power as an opaque object, shows 

 what was once the horny case of these creatures in 

 almost their original form. If a section of this 

 shale is ground very thin and mounted for the mi- 

 croscope, the cases of the Entomostraca are shown 

 almost as transparent as glass. The same shale in 



