It often happens that the eggs laid by the cuckoo are not unlike those of the birds in the nests of which they are deposited. Hence, some naturalists assert that the cuckoo, having laid an egg, flies about with it in her bill until she comes upon a clutch which matches her egg. Perhaps the best reply to this theory is that such refinement on the part of the cuckoo is wholly unnecessary. Most birds, when seized by the mania of incubation, will sit upon anything which even remotely resembles an egg. Mr. Stuart Baker writes that he has not found that there is any proof of the cuckoo trying to match its eggs with those of the intended foster-mother, or that it selects a foster-mother whose eggs shall match its own. He adds that not one of his correspondents has advanced this suggestion, and states that he has little doubt that convenience of site and propinquity to the cuckoo about to lay its eggs are the main requisitions. Almost indistinguishable from the common cuckoo in appearance is the Himalayan cuckoo (_Cuculus saturatus_). The call of this bird, which continues later in the year than that of the common cuckoo, is not unlike the _whoot-whoot-whoot_ of the crow-pheasant or coucal. Perhaps it is even more like the _uk-uk-uk_ of the hoopoe repeated very loudly. It may be syllabised as _cuck-hoo-hoo-hoo-hoo_. Not very much is known about the habits of this species. It is believed to victimise chiefly willow-warblers. The Indian cuckoo (_Cuculus micropterus_) resembles in appearance the two species already described. Blanford speaks of its call as a fine melodious whistle. I would not describe the note as a whistle. To me it sounds like _wherefore_, _wherefore_, impressively and sonorously intoned. The vernacular names _Boukotako_ and _Kyphulpakka_ are onomatopoetic, as is Broken Pekoe Bird, by which name the species is known to many Europeans. Last, but not least of the common Himalayan cuckoos, are the famous brain-fever birds, whose crescendo _brain-fever_, _BRAIN-FEVER_, _BRAIN-FEVER_, which is shrieked at all hours of the day and the night, has called forth untold volumes of awful profanity from jaded Europeans living in the plains, and has earned the highest encomiums of Indians. There are two species of brain-fever bird that disport themselves in the Himalayas. These are known respectively as the large and the common hawk-cuckoo (_Hierococcyx sparverioides_ and _H. varius_). I do not profess to distinguish with certainty between the notes of these two birds, but am under the impression that the larger form is the one that makes itself heard at Naini Tal and Mussoorie.