THE society's NOTE-BOOKS. 99 



body — a correspondino: process of accretion has been taking 

 place, represented by figures a', b', c', d', e', whereby a cal- 

 careous network with hexagonal areolae is formed. By degrees 

 this becomes more shaped, and as a finishing stroke the edges 

 of the network entirely become denticulate, whereby the 

 power of holding to the skin, and s(; aiibrding a firm resting- 

 bed for the anchor, must be very greatly increased. 



Fig. 3. — Mandible of Lithobius forficatus, the ccnnmon brown Centi- 

 pede, X 50, to show the poison-gland, with its investment of 

 spirally arranged, unstriped muscular fibre, the long slender 

 duct, and the slit near the extremity of the fang, where the 

 poison finds exit through a very minute opening. 



,, 4. — Lithobius forjicatiis, as seen with a very low power (x 7). 

 Counting the head as one, it will be found there are twenty- 

 two segments, fifteen joints in the antennae, and twenty pairs 

 of limbs ; thirteen pairs of spiracles, belonging to the 3rd, 

 4th, 5th, 8th, 9th, 11th, 13th, 17th, 19th, and 2 1st segments 

 ■ / respectively. These vary in size, the 3rd, 5th, and 8ch being 



very small, the 18th small, and the remainder of a larger size. 

 g.o shows the genital orifices. 



9 on Plate represents the small spiracle of the 3rd segment, and 

 Fig. 11 one of the larger size from the 11th segment, which is 

 a good average of the large ones, both x 100. 



5. — The mandible of the left side, seen from below, x 50. 



6. — The same, more enlarged, showing the sieve-like openings of 

 the receptaculum veneris and the duct. 



7. — Right mandible from below. At the inner angle is a brush 

 formed of three or four tufts of hairs ; the teeth of the man- 

 dible are seen to be themselves denticulate. 



8. — Labrum and portion of labium. Drawn by Tuflen West. 



5 ) 





>> 



5 5 



Plate II. 

 Upper Portion. 



Head of Male G nat, showing, o,t, at. , antenn?© of fifteen joints ; x cc, 

 the enlarged basal joints. These latter, and the two terminal 

 ones, are free from whorls of hair. Ibr.^ labrum ; ^6., labium ; 

 Ib.p. , labial palpi ; Ig. , lingua. x 20, 



Louver Portion. 



Fig. 1. — Gizzard of Weevil. The entire specimen, as seen with a 

 moderate power. x 90. 



,, 2. —Three of the scale-like teeth, highly magnified. x 400. 



,, 3. — Diagrammatic section of the entire Gizzard, in a distended 

 state. It will be easy to ascertain the nature of the food by 

 examining the contents. In Hylobius abietis, the largest 

 English weevil, portions of the bark of the Scotch fir were 

 contained in a gizzard 1 dissected. In the present instance, 

 I have no doubt the softer portions of leaves of nettle, hazel, 

 and perhaps other plants would be found. 



Drawn by TuflFen West. 



