124 EXPLANATION OF PLATES. 



Fig. 7. — Diagram explaining how the eggs are fertilised and coated 

 with glutinous matter in the parent insect, ovd. , ovd. , two of 

 the oviducts; p., pouch ; c.o., common oviduct; a.g., a.g., 

 albumen glands; r.s., r.s., receptacula seminis of the Blow- 



,, 8. — Diagrammatic representations of the method in which the 

 long stalk is produced, numbered a to d. (See Mr. Tuffen 

 West's notes, page 114.) 



Drawn by TuflFen West. 



Plate XIV. 



Fig. 1. — Acarus from Linnet (Dermanyssus avium). d.s., dorsal 

 shield ; a.s., abdominal shield ; sp., spiracles, x 50 diam. 



,, 2. — Oral organs, x 100 diam. ; m.d.^ m.d.^ mandibles ; pp.^ 

 palpi. 



,, 3. — Portion of a specimen in the j)ossession of the writer, supposed 

 to be a male of the same species, sjj. , spiracle. 



,, 4. — Foot from second limb of right side, x 200 diam. 



,, 5. — Oral organs from a male of Dermanyssus avium, taken from 

 the figure in the Micrographic Dictionary, and put into 

 diagrammatic form for the sake of clearness. 



,, 7. — Male Dermanyssus, x 33 diam., showing remarkable develop- 

 ment of second feet. m. , mentum and labium ; 2?. > palpi ; 

 ch., basal part of chelse (see Fig. 8) ; sp., spiracle ; 

 V.J vent. 



,, 8. — Mouth organs, x 51 diam. ; m., labium and mentum ; p., 

 palpi ; ch', chela when at rest, as shown in Fig. 7 ; ch", chela 

 thrust out and open as for eating. 



,, 9. — Side view of foot, x 166 diam. A front view of the same is 

 much like Mr. West's drawing. Fig. 4, above. 



Figs. 1 to 5 drawn by TuflFen West. 



,, 7 to 9 ,, H. M. J. Underhill. 



Plate XV. 



Upper Part. 



Fig. 1. — Represents the different parts of Gizzard of small foreign 

 Cockroach, as shown on slide, x 25 diam, 



,, 2. — One of the teeth and punctate lateral plates, enlarged to 100 

 diam. 



Drawn by Tuflfen West. 



Lower Portion. 

 ,, 3. — Caligus diaphanus, from " Baird's British Entomostraca." a, 

 lunulas, or sucking discs ; b, antennae ; c, hrst pair of foot- 

 jaws ; d, rudimentary appendages ; e, analogues of the two 

 pairs of jaws in other orders of Crustacea ; /, mouth ; g, 

 organs representing the posterior pair of jaws ; h, second pair 

 of foot-jaws ; i, third pair of foot-jaws ; j, sternal fork ; k, 

 first pair of thoracic feet ; I, second pair of ditto ; w, third 

 pair of feet j n, fourth pair of feet. 



