44 



Melophagus ovinus, Linn. 



Platb IV. 



Fig. 1. Female sheep-tick : la, larva case, each natural size. 



Fig. 2. Male, dorsal view, X8: a, head; 6, thorax; c, abdomen; d, limbs; e, oval 

 bristle-covered disks, which correspond to the points of attachment of wings 

 in other ilies; /, rudimentary halteres or poisers. 

 Fig. 3. Male, veutral view, X8 : jf, A, and i, the three segments of the thorax ; h, the 



external genitals. 

 Fig. 4. Female, dorsal view, X8. 



Fig. 5. Larva case, x8 : a, cephalic end ; h, two rows each of seven shallow indent- 

 ations. 

 Fig. 6. Foot : a, the two claws between which hangs 6, the pinuiform prehensile 

 organ ; c, the tarsi, whose last joint d supports the prehensile organ ; e, 

 distal end of the tibia. 

 Fig. 6a. Prehensile organ, x60 : a, the segmented muscular portion included within 



the tarsus; h, the flexible grasping portion. 

 Fig. 7. Front view of head: a, the compound eyes; T>, the antennae sunk in cup- 

 like cavities ; c, the labrum which protects the sucking organ. 

 Fig. 8. The sucking apparatus: a, the labrum; 6, the orifice from which the tube 



protrudes; c, the sucking tube. 

 Fig. 9. End of the sucking tube, X120: a, teeth by which the tube cuts its way 

 through the skin ; V, rod upon which the teeth are set ; c, tube which has 

 lateral orifice in it. Other details not shown. 

 Fig. 10. External geuital apparatus of female: a, spine-covered cap which fits over 

 6, the genital orifice above; e, two clusters of spines which seem to be for 

 clasping ; d, the terminal of the seven pair of stigmata or breathing pores ; 

 e, anus. 

 Fig. 11. External genital apparatus of male: o, the two lateral of the three chit- 

 inous styles which surround the projecting intromittcut organ ; h, two 

 clusters of spines which seem to be claspers; c, stigmata. 

 Fig. 12. Larva case, X6: a, case with the broken operculum inside ; ft, cephalic end, 

 showing line where the operculum splits off and the remains of a cen- 

 tral orifice through which nourishment was obtained by the embryo from 

 the parent ; c, caudal end showing the two dots corresponding to the two 

 terminal stigmata. 

 Fig. 13. Larva case with larva, X6: a, ventral view; 6, dorsal view. 



