220 Discoveries of Miiller and others in the 



In the preceding list, the Gymnetrus HawkenzV occupies its 

 station on very doubtful authority; while the blade fish, as yet, 

 can be viewed only as a straggler. The latter term may with 

 truth be applied to several other species of reputed British 

 fishes. Those kinds of fish which are sought after as food 

 come frequently under the eye of the ichthyologist. Their 

 haunts are eagerly investigated, and ingenuity is occupied in 

 devising means for their capture ; but those which are deemed 

 useless are permitted to roam about unmolested by the net of 

 the fisher, and at a distance from the temptation of his bait. 

 Such species seldom come under the notice of the naturalist, 

 unless when the weakness of age and other calamities have 

 rendered them the sport of the waves, and consigned them 

 to the beach ; and few are the portions of the coast where 

 the eye of the naturalist habitually examines that store- 

 house of novelties, the rejectamenta of the sea. In the 

 present instance, the scientific zeal of Dr. Duguid has been 

 rewarded by a contribution of no small value to the British 

 fauna, the earnest, it may be hoped, of other rarities from the 

 Orkney seas. 



Manse ofFlisJc^ Feb. 1. 1831. 



Art. VIII. An Account of the Discoveries ofMuller and others in 

 the Organs of Vision of Insects and the Crustacea, By George 

 Parsons, Esq. 



(Continued from p. 134.) 



Compound Eyes of the Crustaceous Animals and Insects, 

 The compound eyes are found in all the Crustacea, and in 

 ^11 winged insects in their perfect state. Amongst the apterous 

 insects they are observed also in the two genera Machilis and 

 Lepisma. They do not exist in the larvae of coleopterous, 

 hymenopterous, dipterous, lepidopterous, nor in most of the 

 neuropterous insects. They occur, how^ever, in some aquatic 

 larvae of the Neuroptera, as the Libellulinae and jEphemeridae ; 

 ;and in the larvae of the orders Orthoptera and Hemiptera. 



Some insects seem to be blind. In the order Coleoptera, all 

 the species of Claviger appear to be so ; amongst the Diptera, 

 ihe genus Braula, a parasite living on bees, and some parasitic 

 species of Pupipara, Nycteribia, and Melophagus have no 

 eyes, or else these orga;ns are very indistinct ; and the neuters 

 of some species of ant are in the same state. 



Of the Crustacea very few, if any, are without eyes. In 

 insects these organs are almost always immovable ; and 

 although in the genera A'chias and Diopsis, dipterous insects 



