...invariably round. " From the fact that in one insect at least, the sheep-tick (Melophagta ovinus), which ranks very low in the scale of development,...this lens, we find that it traverses a vacant space before entering the conical lens, this space being surrounded by the dark pigment already referred...

...invariably round. 4. From the fact that in one insect at least, the sheep tick (Melophagus ovinus), which ranks very low in the scale of development,...facets of the compound eyes non-adherent and circular. A careful examination of the eye in the pupa, whilst in process- of development, confirms the opinion...

...invariablg round. 4. From the fact that in one insect at least, the sheep tick (31clophagus ovinus), which ranks very low in the scale of development,...external facets of the compound eyes non-adherent and cireular. A careful examination of the eye in the pupa, whilst in process of development, confirms...

...the fact that in one inject at least, the sheep-tick (Melophaffus ovinus), which ranks very low iu the scale of development, we find ALL the external...facets of the compound eyes non-adherent and circular.* " This natural diaphragm is so formed, that the amount of light which is permitted to pass is to some...

...least, the sheep-tick (Melophayui minus), which ranks very low in the scale of development, we Cud ALL the external facets of the compound eyes non-adherent...ocellus of the Bee, a compound hexahedral prism with doable convex surfaces. Following the course of a ray of light after it has passed through this lens,...