Do you remember all those cicada videos from the United States in 2021? 

你还记得2021年美国那些蝉视频吗？ 

Well, prepare for a repeat performance this year. The insect show begins as early as April. 

好吧，准备今年重演吧。 昆虫展最早于四月开始。 

Two groups of cicadas, brood XIII and brood XIX, are expected to come out from the ground to mate and lay eggs this year. Their appearance in the same year is rare. The last time it happened was 1803. 

预计今年会有两组蝉，即第十三窝和第十九窝蝉从地里出来交配并产卵。 他们同年出现的情况实属罕见。 上一次发生这种情况是在 1803 年。

Brood XIII is on a 17-year cycle. They will be found in the Midwestern states of Illinois, Iowa, Wisconsin and Kentucky. Brood XIX is on a 13-year cycle. They will come out in an area stretching from Indiana and Illinois southeast to the southern states of Alabama and Georgia. 

《巢穴 XIII》以 17 年为一个周期。 它们分布在中西部的伊利诺伊州、爱荷华州、威斯康星州和肯塔基州。 《Brood XIX》以 13 年为一个周期。 他们将出现的地区从印第安纳州和伊利诺伊州东南部延伸到南部的阿拉巴马州和佐治亚州。 

Scientists expect more than one trillion cicadas to appear in some small areas where the two broods are close to each other. The insects will begin to climb out of the ground when the soil warms to about 18 degrees Celsius. So they will be seen in warmer southern areas as early as April. It will be closer to summer, sometime in June, before the cicadas arise to the north in Wisconsin, Indiana and other Midwestern states. 

科学家预计超过一万亿只蝉会出现在两窝蝉彼此靠近的一些小区域。 当土壤变暖到18摄氏度左右时，昆虫就会开始爬出地面。 因此，最早在四月就可以在温暖的南部地区看到它们。 六月的某个时候，夏天将临近，此时蝉会在威斯康星州、印第安纳州和其他中西部各州的北部出现。 

Cicadas are large, noisy insects, from about 2.5 to 5 centimeters long. Like most insects, they have wings. They also have big “bulging” eyes. There are thousands of species of cicada around the world. 

蝉是一种大型、吵闹的昆虫，长约 2.5 至 5 厘米。 像大多数昆虫一样，它们有翅膀。 他们还有“凸出”的大眼睛。 世界各地有数千种蝉。 

The huge majority of cicada species arise each year, or annually. Then there are the periodicals which arrive after numerous years in the ground. 

绝大多数蝉物种每年都会出现。 还有一些在地下多年后才出现的期刊。

The periodical cicadas emerge to mate. 

周期性蝉出现交配。

The male cicadas make a thrumming sound with their wings on their bodies to call for mating. The “singing” appeals to females. The insects mate and leave their fertilized eggs on trees. The resulting young fall to the ground after breaking out of their shells. They dig down into the ground where they live for years, feeding on the liquid that comes from tree roots. 

雄性蝉用身体上的翅膀发出嗡嗡的声音，以求交配。 “歌声”对女性有吸引力。 这些昆虫交配并将受精卵留在树上。 由此产生的幼崽破壳后掉落在地上。 它们在生活了多年的地下挖洞，以树根的液体为食。 

Seven of the nine known periodical cicadas live in North America. Of the other two groups, one is in India and one is found only on the island country of Fiji. 

已知的九种周期性蝉中有七种生活在北美。 另外两组中，一组在印度，一组仅在岛国斐济发现。 

Floyd Shockley is an insect scientist, or entomologist, with the Smithsonian Institution’s National Museum of Natural History in Washington, D.C. He said this year’s group of cicadas will include four different Magicada species within the XIX brood. 

弗洛伊德·肖克利 (Floyd Shockley) 是华盛顿特区史密森尼学会国家自然历史博物馆的一名昆虫科学家或昆虫学家。他说，今年的蝉群将包括 XIX 窝中的四种不同的 Magicada 物种。 

The next time brood XIX and brood XIII will come out in the same year will be in 2245. 

下一次《巢穴 XIX》和《巢穴 XIII》同年推出是在 2245 年。